Adding upstream version 1.20.14.upstream/1.20.14upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3844 insertions, 0 deletions

diff --git a/src/crypto/x509/x509_test.go b/src/crypto/x509/x509_test.go
new file mode 100644
index 0000000..8846b00
--- /dev/null
+++ b/src/crypto/x509/x509_test.go
@@ -0,0 +1,3844 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package x509
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdh"
+	"crypto/ecdsa"
+	"crypto/ed25519"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/rsa"
+	_ "crypto/sha256"
+	_ "crypto/sha512"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/pem"
+	"fmt"
+	"internal/testenv"
+	"io"
+	"math/big"
+	"net"
+	"net/url"
+	"os/exec"
+	"reflect"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestParsePKCS1PrivateKey(t *testing.T) {
+	block, _ := pem.Decode([]byte(pemPrivateKey))
+	priv, err := ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		t.Errorf("Failed to parse private key: %s", err)
+		return
+	}
+	if priv.PublicKey.N.Cmp(rsaPrivateKey.PublicKey.N) != 0 ||
+		priv.PublicKey.E != rsaPrivateKey.PublicKey.E ||
+		priv.D.Cmp(rsaPrivateKey.D) != 0 ||
+		priv.Primes[0].Cmp(rsaPrivateKey.Primes[0]) != 0 ||
+		priv.Primes[1].Cmp(rsaPrivateKey.Primes[1]) != 0 {
+		t.Errorf("got:%+v want:%+v", priv, rsaPrivateKey)
+	}
+
+	// This private key includes an invalid prime that
+	// rsa.PrivateKey.Validate should reject.
+	data := []byte("0\x16\x02\x00\x02\x02\u007f\x00\x02\x0200\x02\x0200\x02\x02\x00\x01\x02\x02\u007f\x00")
+	if _, err := ParsePKCS1PrivateKey(data); err == nil {
+		t.Errorf("parsing invalid private key did not result in an error")
+	}
+}
+
+func TestPKCS1MismatchPublicKeyFormat(t *testing.T) {
+
+	const pkixPublicKey = "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"
+	const errorContains = "use ParsePKIXPublicKey instead"
+	derBytes, _ := hex.DecodeString(pkixPublicKey)
+	_, err := ParsePKCS1PublicKey(derBytes)
+	if !strings.Contains(err.Error(), errorContains) {
+		t.Errorf("expected error containing %q, got %s", errorContains, err)
+	}
+}
+
+func TestMarshalInvalidPublicKey(t *testing.T) {
+	_, err := MarshalPKIXPublicKey(&ecdsa.PublicKey{})
+	if err == nil {
+		t.Errorf("expected error, got MarshalPKIXPublicKey success")
+	}
+	_, err = MarshalPKIXPublicKey(&ecdsa.PublicKey{
+		Curve: elliptic.P256(),
+		X:     big.NewInt(1), Y: big.NewInt(2),
+	})
+	if err == nil {
+		t.Errorf("expected error, got MarshalPKIXPublicKey success")
+	}
+}
+
+func testParsePKIXPublicKey(t *testing.T, pemBytes string) (pub any) {
+	block, _ := pem.Decode([]byte(pemBytes))
+	pub, err := ParsePKIXPublicKey(block.Bytes)
+	if err != nil {
+		t.Fatalf("Failed to parse public key: %s", err)
+	}
+
+	pubBytes2, err := MarshalPKIXPublicKey(pub)
+	if err != nil {
+		t.Errorf("Failed to marshal public key for the second time: %s", err)
+		return
+	}
+	if !bytes.Equal(pubBytes2, block.Bytes) {
+		t.Errorf("Reserialization of public key didn't match. got %x, want %x", pubBytes2, block.Bytes)
+	}
+	return
+}
+
+func TestParsePKIXPublicKey(t *testing.T) {
+	t.Run("RSA", func(t *testing.T) {
+		pub := testParsePKIXPublicKey(t, pemPublicKey)
+		_, ok := pub.(*rsa.PublicKey)
+		if !ok {
+			t.Errorf("Value returned from ParsePKIXPublicKey was not an RSA public key")
+		}
+	})
+	t.Run("Ed25519", func(t *testing.T) {
+		pub := testParsePKIXPublicKey(t, pemEd25519Key)
+		_, ok := pub.(ed25519.PublicKey)
+		if !ok {
+			t.Errorf("Value returned from ParsePKIXPublicKey was not an Ed25519 public key")
+		}
+	})
+	t.Run("X25519", func(t *testing.T) {
+		pub := testParsePKIXPublicKey(t, pemX25519Key)
+		k, ok := pub.(*ecdh.PublicKey)
+		if !ok || k.Curve() != ecdh.X25519() {
+			t.Errorf("Value returned from ParsePKIXPublicKey was not an X25519 public key")
+		}
+	})
+}
+
+var pemPublicKey = `-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA3VoPN9PKUjKFLMwOge6+
+wnDi8sbETGIx2FKXGgqtAKpzmem53kRGEQg8WeqRmp12wgp74TGpkEXsGae7RS1k
+enJCnma4fii+noGH7R0qKgHvPrI2Bwa9hzsH8tHxpyM3qrXslOmD45EH9SxIDUBJ
+FehNdaPbLP1gFyahKMsdfxFJLUvbUycuZSJ2ZnIgeVxwm4qbSvZInL9Iu4FzuPtg
+fINKcbbovy1qq4KvPIrXzhbY3PWDc6btxCf3SE0JdE1MCPThntB62/bLMSQ7xdDR
+FF53oIpvxe/SCOymfWq/LW849Ytv3Xwod0+wzAP8STXG4HSELS4UedPYeHJJJYcZ
++QIDAQAB
+-----END PUBLIC KEY-----
+`
+
+var pemPrivateKey = testingKey(`
+-----BEGIN RSA TESTING KEY-----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+-----END RSA TESTING KEY-----
+`)
+
+// pemEd25519Key is the example from RFC 8410, Secrion 4.
+var pemEd25519Key = `
+-----BEGIN PUBLIC KEY-----
+MCowBQYDK2VwAyEAGb9ECWmEzf6FQbrBZ9w7lshQhqowtrbLDFw4rXAxZuE=
+-----END PUBLIC KEY-----
+`
+
+// pemX25519Key was generated from pemX25519Key with "openssl pkey -pubout".
+var pemX25519Key = `
+-----BEGIN PUBLIC KEY-----
+MCowBQYDK2VuAyEA5yGXrH/6OzxuWEhEWS01/f4OP+Of3Yrddy6/J1kDTVM=
+-----END PUBLIC KEY-----
+`
+
+func TestPKIXMismatchPublicKeyFormat(t *testing.T) {
+
+	const pkcs1PublicKey = "308201080282010100817cfed98bcaa2e2a57087451c7674e0c675686dc33ff1268b0c2a6ee0202dec710858ee1c31bdf5e7783582e8ca800be45f3275c6576adc35d98e26e95bb88ca5beb186f853b8745d88bc9102c5f38753bcda519fb05948d5c77ac429255ff8aaf27d9f45d1586e95e2e9ba8a7cb771b8a09dd8c8fed3f933fd9b439bc9f30c475953418ef25f71a2b6496f53d94d39ce850aa0cc75d445b5f5b4f4ee4db78ab197a9a8d8a852f44529a007ac0ac23d895928d60ba538b16b0b087a7f903ed29770e215019b77eaecc360f35f7ab11b6d735978795b2c4a74e5bdea4dc6594cd67ed752a108e666729a753ab36d6c4f606f8760f507e1765be8cd744007e629020103"
+	const errorContains = "use ParsePKCS1PublicKey instead"
+	derBytes, _ := hex.DecodeString(pkcs1PublicKey)
+	_, err := ParsePKIXPublicKey(derBytes)
+	if !strings.Contains(err.Error(), errorContains) {
+		t.Errorf("expected error containing %q, got %s", errorContains, err)
+	}
+}
+
+var testPrivateKey *rsa.PrivateKey
+
+func init() {
+	block, _ := pem.Decode([]byte(pemPrivateKey))
+
+	var err error
+	if testPrivateKey, err = ParsePKCS1PrivateKey(block.Bytes); err != nil {
+		panic("Failed to parse private key: " + err.Error())
+	}
+}
+
+func bigFromString(s string) *big.Int {
+	ret := new(big.Int)
+	ret.SetString(s, 10)
+	return ret
+}
+
+func fromBase10(base10 string) *big.Int {
+	i := new(big.Int)
+	i.SetString(base10, 10)
+	return i
+}
+
+func bigFromHexString(s string) *big.Int {
+	ret := new(big.Int)
+	ret.SetString(s, 16)
+	return ret
+}
+
+var rsaPrivateKey = &rsa.PrivateKey{
+	PublicKey: rsa.PublicKey{
+		N: bigFromString("124737666279038955318614287965056875799409043964547386061640914307192830334599556034328900586693254156136128122194531292927142396093148164407300419162827624945636708870992355233833321488652786796134504707628792159725681555822420087112284637501705261187690946267527866880072856272532711620639179596808018872997"),
+		E: 65537,
+	},
+	D: bigFromString("69322600686866301945688231018559005300304807960033948687567105312977055197015197977971637657636780793670599180105424702854759606794705928621125408040473426339714144598640466128488132656829419518221592374964225347786430566310906679585739468938549035854760501049443920822523780156843263434219450229353270690889"),
+	Primes: []*big.Int{
+		bigFromString("11405025354575369741595561190164746858706645478381139288033759331174478411254205003127028642766986913445391069745480057674348716675323735886284176682955723"),
+		bigFromString("10937079261204603443118731009201819560867324167189758120988909645641782263430128449826989846631183550578761324239709121189827307416350485191350050332642639"),
+	},
+}
+
+func TestMarshalRSAPrivateKey(t *testing.T) {
+	priv := &rsa.PrivateKey{
+		PublicKey: rsa.PublicKey{
+			N: fromBase10("16346378922382193400538269749936049106320265317511766357599732575277382844051791096569333808598921852351577762718529818072849191122419410612033592401403764925096136759934497687765453905884149505175426053037420486697072448609022753683683718057795566811401938833367954642951433473337066311978821180526439641496973296037000052546108507805269279414789035461158073156772151892452251106173507240488993608650881929629163465099476849643165682709047462010581308719577053905787496296934240246311806555924593059995202856826239801816771116902778517096212527979497399966526283516447337775509777558018145573127308919204297111496233"),
+			E: 3,
+		},
+		D: fromBase10("10897585948254795600358846499957366070880176878341177571733155050184921896034527397712889205732614568234385175145686545381899460748279607074689061600935843283397424506622998458510302603922766336783617368686090042765718290914099334449154829375179958369993407724946186243249568928237086215759259909861748642124071874879861299389874230489928271621259294894142840428407196932444474088857746123104978617098858619445675532587787023228852383149557470077802718705420275739737958953794088728369933811184572620857678792001136676902250566845618813972833750098806496641114644760255910789397593428910198080271317419213080834885003"),
+		Primes: []*big.Int{
+			fromBase10("1025363189502892836833747188838978207017355117492483312747347695538428729137306368764177201532277413433182799108299960196606011786562992097313508180436744488171474690412562218914213688661311117337381958560443"),
+			fromBase10("3467903426626310123395340254094941045497208049900750380025518552334536945536837294961497712862519984786362199788654739924501424784631315081391467293694361474867825728031147665777546570788493758372218019373"),
+			fromBase10("4597024781409332673052708605078359346966325141767460991205742124888960305710298765592730135879076084498363772408626791576005136245060321874472727132746643162385746062759369754202494417496879741537284589047"),
+		},
+	}
+
+	derBytes := MarshalPKCS1PrivateKey(priv)
+
+	priv2, err := ParsePKCS1PrivateKey(derBytes)
+	if err != nil {
+		t.Errorf("error parsing serialized key: %s", err)
+		return
+	}
+	if priv.PublicKey.N.Cmp(priv2.PublicKey.N) != 0 ||
+		priv.PublicKey.E != priv2.PublicKey.E ||
+		priv.D.Cmp(priv2.D) != 0 ||
+		len(priv2.Primes) != 3 ||
+		priv.Primes[0].Cmp(priv2.Primes[0]) != 0 ||
+		priv.Primes[1].Cmp(priv2.Primes[1]) != 0 ||
+		priv.Primes[2].Cmp(priv2.Primes[2]) != 0 {
+		t.Errorf("got:%+v want:%+v", priv, priv2)
+	}
+}
+
+func TestMarshalRSAPublicKey(t *testing.T) {
+	pub := &rsa.PublicKey{
+		N: fromBase10("16346378922382193400538269749936049106320265317511766357599732575277382844051791096569333808598921852351577762718529818072849191122419410612033592401403764925096136759934497687765453905884149505175426053037420486697072448609022753683683718057795566811401938833367954642951433473337066311978821180526439641496973296037000052546108507805269279414789035461158073156772151892452251106173507240488993608650881929629163465099476849643165682709047462010581308719577053905787496296934240246311806555924593059995202856826239801816771116902778517096212527979497399966526283516447337775509777558018145573127308919204297111496233"),
+		E: 3,
+	}
+	derBytes := MarshalPKCS1PublicKey(pub)
+	pub2, err := ParsePKCS1PublicKey(derBytes)
+	if err != nil {
+		t.Errorf("ParsePKCS1PublicKey: %s", err)
+	}
+	if pub.N.Cmp(pub2.N) != 0 || pub.E != pub2.E {
+		t.Errorf("ParsePKCS1PublicKey = %+v, want %+v", pub, pub2)
+	}
+
+	// It's never been documented that asn1.Marshal/Unmarshal on rsa.PublicKey works,
+	// but it does, and we know of code that depends on it.
+	// Lock that in, even though we'd prefer that people use MarshalPKCS1PublicKey and ParsePKCS1PublicKey.
+	derBytes2, err := asn1.Marshal(*pub)
+	if err != nil {
+		t.Errorf("Marshal(rsa.PublicKey): %v", err)
+	} else if !bytes.Equal(derBytes, derBytes2) {
+		t.Errorf("Marshal(rsa.PublicKey) = %x, want %x", derBytes2, derBytes)
+	}
+	pub3 := new(rsa.PublicKey)
+	rest, err := asn1.Unmarshal(derBytes, pub3)
+	if err != nil {
+		t.Errorf("Unmarshal(rsa.PublicKey): %v", err)
+	}
+	if len(rest) != 0 || pub.N.Cmp(pub3.N) != 0 || pub.E != pub3.E {
+		t.Errorf("Unmarshal(rsa.PublicKey) = %+v, %q want %+v, %q", pub, rest, pub2, []byte(nil))
+	}
+
+	publicKeys := []struct {
+		derBytes          []byte
+		expectedErrSubstr string
+	}{
+		{
+			derBytes: []byte{
+				0x30, 6, // SEQUENCE, 6 bytes
+				0x02, 1, // INTEGER, 1 byte
+				17,
+				0x02, 1, // INTEGER, 1 byte
+				3, // 3
+			},
+		}, {
+			derBytes: []byte{
+				0x30, 6, // SEQUENCE
+				0x02, 1, // INTEGER, 1 byte
+				0xff,    // -1
+				0x02, 1, // INTEGER, 1 byte
+				3,
+			},
+			expectedErrSubstr: "zero or negative",
+		}, {
+			derBytes: []byte{
+				0x30, 6, // SEQUENCE
+				0x02, 1, // INTEGER, 1 byte
+				17,
+				0x02, 1, // INTEGER, 1 byte
+				0xff, // -1
+			},
+			expectedErrSubstr: "zero or negative",
+		}, {
+			derBytes: []byte{
+				0x30, 6, // SEQUENCE
+				0x02, 1, // INTEGER, 1 byte
+				17,
+				0x02, 1, // INTEGER, 1 byte
+				3,
+				1,
+			},
+			expectedErrSubstr: "trailing data",
+		}, {
+			derBytes: []byte{
+				0x30, 9, // SEQUENCE
+				0x02, 1, // INTEGER, 1 byte
+				17,
+				0x02, 4, // INTEGER, 4 bytes
+				0x7f, 0xff, 0xff, 0xff,
+			},
+		}, {
+			derBytes: []byte{
+				0x30, 10, // SEQUENCE
+				0x02, 1, // INTEGER, 1 byte
+				17,
+				0x02, 5, // INTEGER, 5 bytes
+				0x00, 0x80, 0x00, 0x00, 0x00,
+			},
+			// On 64-bit systems, encoding/asn1 will accept the
+			// public exponent, but ParsePKCS1PublicKey will return
+			// an error. On 32-bit systems, encoding/asn1 will
+			// return the error. The common substring of both error
+			// is the word “large”.
+			expectedErrSubstr: "large",
+		},
+	}
+
+	for i, test := range publicKeys {
+		shouldFail := len(test.expectedErrSubstr) > 0
+		pub, err := ParsePKCS1PublicKey(test.derBytes)
+		if shouldFail {
+			if err == nil {
+				t.Errorf("#%d: unexpected success, got %#v", i, pub)
+			} else if !strings.Contains(err.Error(), test.expectedErrSubstr) {
+				t.Errorf("#%d: expected error containing %q, got %s", i, test.expectedErrSubstr, err)
+			}
+		} else {
+			if err != nil {
+				t.Errorf("#%d: unexpected failure: %s", i, err)
+				continue
+			}
+			reserialized := MarshalPKCS1PublicKey(pub)
+			if !bytes.Equal(reserialized, test.derBytes) {
+				t.Errorf("#%d: failed to reserialize: got %x, expected %x", i, reserialized, test.derBytes)
+			}
+		}
+	}
+}
+
+type matchHostnamesTest struct {
+	pattern, host string
+	ok            bool
+}
+
+var matchHostnamesTests = []matchHostnamesTest{
+	{"a.b.c", "a.b.c", true},
+	{"a.b.c", "b.b.c", false},
+	{"", "b.b.c", false},
+	{"a.b.c", "", false},
+	{"example.com", "example.com", true},
+	{"example.com", "www.example.com", false},
+	{"*.example.com", "example.com", false},
+	{"*.example.com", "www.example.com", true},
+	{"*.example.com", "www.example.com.", true},
+	{"*.example.com", "xyz.www.example.com", false},
+	{"*.example.com", "https://www.example.com", false}, // Issue 27591
+	{"*.example..com", "www.example..com", false},
+	{"www.example..com", "www.example..com", true},
+	{"*.*.example.com", "xyz.www.example.com", false},
+	{"*.www.*.com", "xyz.www.example.com", false},
+	{"*bar.example.com", "foobar.example.com", false},
+	{"f*.example.com", "foobar.example.com", false},
+	{"www.example.com", "*.example.com", false},
+	{"", ".", false},
+	{".", "", false},
+	{".", ".", false},
+	{"example.com", "example.com.", true},
+	{"example.com.", "example.com", false},
+	{"example.com.", "example.com.", true}, // perfect matches allow trailing dots in patterns
+	{"*.com.", "example.com.", false},
+	{"*.com.", "example.com", false},
+	{"*.com", "example.com", true},
+	{"*.com", "example.com.", true},
+	{"foo:bar", "foo:bar", true},
+	{"*.foo:bar", "xxx.foo:bar", false},
+	{"*.2.3.4", "1.2.3.4", false},
+	{"*.2.3.4", "[1.2.3.4]", false},
+	{"*:4860:4860::8888", "2001:4860:4860::8888", false},
+	{"*:4860:4860::8888", "[2001:4860:4860::8888]", false},
+	{"2001:4860:4860::8888", "2001:4860:4860::8888", false},
+	{"2001:4860:4860::8888", "[2001:4860:4860::8888]", false},
+	{"[2001:4860:4860::8888]", "2001:4860:4860::8888", false},
+	{"[2001:4860:4860::8888]", "[2001:4860:4860::8888]", false},
+}
+
+func TestMatchHostnames(t *testing.T) {
+	for i, test := range matchHostnamesTests {
+		c := &Certificate{DNSNames: []string{test.pattern}}
+		r := c.VerifyHostname(test.host) == nil
+		if r != test.ok {
+			t.Errorf("#%d mismatch got: %t want: %t when matching '%s' against '%s'", i, r, test.ok, test.host, test.pattern)
+		}
+	}
+}
+
+func TestMatchIP(t *testing.T) {
+	// Check that pattern matching is working.
+	c := &Certificate{
+		DNSNames: []string{"*.foo.bar.baz"},
+		Subject: pkix.Name{
+			CommonName: "*.foo.bar.baz",
+		},
+	}
+	err := c.VerifyHostname("quux.foo.bar.baz")
+	if err != nil {
+		t.Fatalf("VerifyHostname(quux.foo.bar.baz): %v", err)
+	}
+
+	// But check that if we change it to be matching against an IP address,
+	// it is rejected.
+	c = &Certificate{
+		DNSNames: []string{"*.2.3.4"},
+		Subject: pkix.Name{
+			CommonName: "*.2.3.4",
+		},
+	}
+	err = c.VerifyHostname("1.2.3.4")
+	if err == nil {
+		t.Fatalf("VerifyHostname(1.2.3.4) should have failed, did not")
+	}
+
+	c = &Certificate{
+		IPAddresses: []net.IP{net.ParseIP("127.0.0.1"), net.ParseIP("::1")},
+	}
+	err = c.VerifyHostname("127.0.0.1")
+	if err != nil {
+		t.Fatalf("VerifyHostname(127.0.0.1): %v", err)
+	}
+	err = c.VerifyHostname("::1")
+	if err != nil {
+		t.Fatalf("VerifyHostname(::1): %v", err)
+	}
+	err = c.VerifyHostname("[::1]")
+	if err != nil {
+		t.Fatalf("VerifyHostname([::1]): %v", err)
+	}
+}
+
+func TestCertificateParse(t *testing.T) {
+	s, _ := base64.StdEncoding.DecodeString(certBytes)
+	certs, err := ParseCertificates(s)
+	if err != nil {
+		t.Error(err)
+	}
+	if len(certs) != 2 {
+		t.Errorf("Wrong number of certs: got %d want 2", len(certs))
+		return
+	}
+
+	err = certs[0].CheckSignatureFrom(certs[1])
+	if err != nil {
+		t.Error(err)
+	}
+
+	if err := certs[0].VerifyHostname("mail.google.com"); err != nil {
+		t.Error(err)
+	}
+
+	const expectedExtensions = 10
+	if n := len(certs[0].Extensions); n != expectedExtensions {
+		t.Errorf("want %d extensions, got %d", expectedExtensions, n)
+	}
+}
+
+func TestCertificateEqualOnNil(t *testing.T) {
+	cNonNil := new(Certificate)
+	var cNil1, cNil2 *Certificate
+	if !cNil1.Equal(cNil2) {
+		t.Error("Nil certificates: cNil1 is not equal to cNil2")
+	}
+	if !cNil2.Equal(cNil1) {
+		t.Error("Nil certificates: cNil2 is not equal to cNil1")
+	}
+	if cNil1.Equal(cNonNil) {
+		t.Error("Unexpectedly cNil1 is equal to cNonNil")
+	}
+	if cNonNil.Equal(cNil1) {
+		t.Error("Unexpectedly cNonNil is equal to cNil1")
+	}
+}
+
+func TestMismatchedSignatureAlgorithm(t *testing.T) {
+	der, _ := pem.Decode([]byte(rsaPSSSelfSignedPEM))
+	if der == nil {
+		t.Fatal("Failed to find PEM block")
+	}
+
+	cert, err := ParseCertificate(der.Bytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err = cert.CheckSignature(ECDSAWithSHA256, nil, nil); err == nil {
+		t.Fatal("CheckSignature unexpectedly return no error")
+	}
+
+	const expectedSubstring = " but have public key of type "
+	if !strings.Contains(err.Error(), expectedSubstring) {
+		t.Errorf("Expected error containing %q, but got %q", expectedSubstring, err)
+	}
+}
+
+var certBytes = "MIIE0jCCA7qgAwIBAgIQWcvS+TTB3GwCAAAAAGEAWzANBgkqhkiG9w0BAQsFADBCMQswCQYD" +
+	"VQQGEwJVUzEeMBwGA1UEChMVR29vZ2xlIFRydXN0IFNlcnZpY2VzMRMwEQYDVQQDEwpHVFMg" +
+	"Q0EgMU8xMB4XDTIwMDQwMTEyNTg1NloXDTIwMDYyNDEyNTg1NlowaTELMAkGA1UEBhMCVVMx" +
+	"EzARBgNVBAgTCkNhbGlmb3JuaWExFjAUBgNVBAcTDU1vdW50YWluIFZpZXcxEzARBgNVBAoT" +
+	"Ckdvb2dsZSBMTEMxGDAWBgNVBAMTD21haWwuZ29vZ2xlLmNvbTBZMBMGByqGSM49AgEGCCqG" +
+	"SM49AwEHA0IABO+dYiPnkFl+cZVf6mrWeNp0RhQcJSBGH+sEJxjvc+cYlW3QJCnm57qlpFdd" +
+	"pz3MPyVejvXQdM6iI1mEWP4C2OujggJmMIICYjAOBgNVHQ8BAf8EBAMCB4AwEwYDVR0lBAww" +
+	"CgYIKwYBBQUHAwEwDAYDVR0TAQH/BAIwADAdBgNVHQ4EFgQUI6pZhnQ/lQgmPDwSKR2A54G7" +
+	"AS4wHwYDVR0jBBgwFoAUmNH4bhDrz5vsYJ8YkBug630J/SswZAYIKwYBBQUHAQEEWDBWMCcG" +
+	"CCsGAQUFBzABhhtodHRwOi8vb2NzcC5wa2kuZ29vZy9ndHMxbzEwKwYIKwYBBQUHMAKGH2h0" +
+	"dHA6Ly9wa2kuZ29vZy9nc3IyL0dUUzFPMS5jcnQwLAYDVR0RBCUwI4IPbWFpbC5nb29nbGUu" +
+	"Y29tghBpbmJveC5nb29nbGUuY29tMCEGA1UdIAQaMBgwCAYGZ4EMAQICMAwGCisGAQQB1nkC" +
+	"BQMwLwYDVR0fBCgwJjAkoCKgIIYeaHR0cDovL2NybC5wa2kuZ29vZy9HVFMxTzEuY3JsMIIB" +
+	"AwYKKwYBBAHWeQIEAgSB9ASB8QDvAHYAsh4FzIuizYogTodm+Su5iiUgZ2va+nDnsklTLe+L" +
+	"kF4AAAFxNgmxKgAABAMARzBFAiEA12/OHdTGXQ3qHHC3NvYCyB8aEz/+ZFOLCAI7lhqj28sC" +
+	"IG2/7Yz2zK6S6ai+dH7cTMZmoFGo39gtaTqtZAqEQX7nAHUAXqdz+d9WwOe1Nkh90EngMnqR" +
+	"mgyEoRIShBh1loFxRVgAAAFxNgmxTAAABAMARjBEAiA7PNq+MFfv6O9mBkxFViS2TfU66yRB" +
+	"/njcebWglLQjZQIgOyRKhxlEizncFRml7yn4Bg48ktXKGjo+uiw6zXEINb0wDQYJKoZIhvcN" +
+	"AQELBQADggEBADM2Rh306Q10PScsolYMxH1B/K4Nb2WICvpY0yDPJFdnGjqCYym196TjiEvs" +
+	"R6etfeHdyzlZj6nh82B4TVyHjiWM02dQgPalOuWQcuSy0OvLh7F1E7CeHzKlczdFPBTOTdM1" +
+	"RDTxlvw1bAqc0zueM8QIAyEy3opd7FxAcGQd5WRIJhzLBL+dbbMOW/LTeW7cm/Xzq8cgCybN" +
+	"BSZAvhjseJ1L29OlCTZL97IfnX0IlFQzWuvvHy7V2B0E3DHlzM0kjwkkCKDUUp/wajv2NZKC" +
+	"TkhEyERacZRKc9U0ADxwsAzHrdz5+5zfD2usEV/MQ5V6d8swLXs+ko0X6swrd4YCiB8wggRK" +
+	"MIIDMqADAgECAg0B47SaoY2KqYElaVC4MA0GCSqGSIb3DQEBCwUAMEwxIDAeBgNVBAsTF0ds" +
+	"b2JhbFNpZ24gUm9vdCBDQSAtIFIyMRMwEQYDVQQKEwpHbG9iYWxTaWduMRMwEQYDVQQDEwpH" +
+	"bG9iYWxTaWduMB4XDTE3MDYxNTAwMDA0MloXDTIxMTIxNTAwMDA0MlowQjELMAkGA1UEBhMC" +
+	"VVMxHjAcBgNVBAoTFUdvb2dsZSBUcnVzdCBTZXJ2aWNlczETMBEGA1UEAxMKR1RTIENBIDFP" +
+	"MTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBANAYz0XUi83TnORA73603WkhG8nP" +
+	"PI5MdbkPMRmEPZ48Ke9QDRCTbwWAgJ8qoL0SSwLhPZ9YFiT+MJ8LdHdVkx1L903hkoIQ9lGs" +
+	"DMOyIpQPNGuYEEnnC52DOd0gxhwt79EYYWXnI4MgqCMS/9Ikf9Qv50RqW03XUGawr55CYwX7" +
+	"4BzEY2Gvn2oz/2KXvUjZ03wUZ9x13C5p6PhteGnQtxAFuPExwjsk/RozdPgj4OxrGYoWxuPN" +
+	"pM0L27OkWWA4iDutHbnGjKdTG/y82aSrvN08YdeTFZjugb2P4mRHIEAGTtesl+i5wFkSoUkl" +
+	"I+TtcDQspbRjfPmjPYPRzW0krAcCAwEAAaOCATMwggEvMA4GA1UdDwEB/wQEAwIBhjAdBgNV" +
+	"HSUEFjAUBggrBgEFBQcDAQYIKwYBBQUHAwIwEgYDVR0TAQH/BAgwBgEB/wIBADAdBgNVHQ4E" +
+	"FgQUmNH4bhDrz5vsYJ8YkBug630J/SswHwYDVR0jBBgwFoAUm+IHV2ccHsBqBt5ZtJot39wZ" +
+	"hi4wNQYIKwYBBQUHAQEEKTAnMCUGCCsGAQUFBzABhhlodHRwOi8vb2NzcC5wa2kuZ29vZy9n" +
+	"c3IyMDIGA1UdHwQrMCkwJ6AloCOGIWh0dHA6Ly9jcmwucGtpLmdvb2cvZ3NyMi9nc3IyLmNy" +
+	"bDA/BgNVHSAEODA2MDQGBmeBDAECAjAqMCgGCCsGAQUFBwIBFhxodHRwczovL3BraS5nb29n" +
+	"L3JlcG9zaXRvcnkvMA0GCSqGSIb3DQEBCwUAA4IBAQAagD42efvzLqlGN31eVBY1rsdOCJn+" +
+	"vdE0aSZSZgc9CrpJy2L08RqO/BFPaJZMdCvTZ96yo6oFjYRNTCBlD6WW2g0W+Gw7228EI4hr" +
+	"OmzBYL1on3GO7i1YNAfw1VTphln9e14NIZT1jMmo+NjyrcwPGvOap6kEJ/mjybD/AnhrYbrH" +
+	"NSvoVvpPwxwM7bY8tEvq7czhPOzcDYzWPpvKQliLzBYhF0C8otZm79rEFVvNiaqbCSbnMtIN" +
+	"bmcgAlsQsJAJnAwfnq3YO+qh/GzoEFwIUhlRKnG7rHq13RXtK8kIKiyKtKYhq2P/11JJUNCJ" +
+	"t63yr/tQri/hlQ3zRq2dnPXK"
+
+func parseCIDR(s string) *net.IPNet {
+	_, net, err := net.ParseCIDR(s)
+	if err != nil {
+		panic(err)
+	}
+	return net
+}
+
+func parseURI(s string) *url.URL {
+	uri, err := url.Parse(s)
+	if err != nil {
+		panic(err)
+	}
+	return uri
+}
+
+func TestCreateSelfSignedCertificate(t *testing.T) {
+	random := rand.Reader
+
+	ecdsaPriv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatalf("Failed to generate ECDSA key: %s", err)
+	}
+
+	ed25519Pub, ed25519Priv, err := ed25519.GenerateKey(random)
+	if err != nil {
+		t.Fatalf("Failed to generate Ed25519 key: %s", err)
+	}
+
+	tests := []struct {
+		name      string
+		pub, priv any
+		checkSig  bool
+		sigAlgo   SignatureAlgorithm
+	}{
+		{"RSA/RSA", &testPrivateKey.PublicKey, testPrivateKey, true, SHA384WithRSA},
+		{"RSA/ECDSA", &testPrivateKey.PublicKey, ecdsaPriv, false, ECDSAWithSHA384},
+		{"ECDSA/RSA", &ecdsaPriv.PublicKey, testPrivateKey, false, SHA256WithRSA},
+		{"ECDSA/ECDSA", &ecdsaPriv.PublicKey, ecdsaPriv, true, ECDSAWithSHA256},
+		{"RSAPSS/RSAPSS", &testPrivateKey.PublicKey, testPrivateKey, true, SHA256WithRSAPSS},
+		{"ECDSA/RSAPSS", &ecdsaPriv.PublicKey, testPrivateKey, false, SHA256WithRSAPSS},
+		{"RSAPSS/ECDSA", &testPrivateKey.PublicKey, ecdsaPriv, false, ECDSAWithSHA384},
+		{"Ed25519", ed25519Pub, ed25519Priv, true, PureEd25519},
+	}
+
+	testExtKeyUsage := []ExtKeyUsage{ExtKeyUsageClientAuth, ExtKeyUsageServerAuth}
+	testUnknownExtKeyUsage := []asn1.ObjectIdentifier{[]int{1, 2, 3}, []int{2, 59, 1}}
+	extraExtensionData := []byte("extra extension")
+
+	for _, test := range tests {
+		commonName := "test.example.com"
+		template := Certificate{
+			SerialNumber: big.NewInt(1),
+			Subject: pkix.Name{
+				CommonName:   commonName,
+				Organization: []string{"Σ Acme Co"},
+				Country:      []string{"US"},
+				ExtraNames: []pkix.AttributeTypeAndValue{
+					{
+						Type:  []int{2, 5, 4, 42},
+						Value: "Gopher",
+					},
+					// This should override the Country, above.
+					{
+						Type:  []int{2, 5, 4, 6},
+						Value: "NL",
+					},
+				},
+			},
+			NotBefore: time.Unix(1000, 0),
+			NotAfter:  time.Unix(100000, 0),
+
+			SignatureAlgorithm: test.sigAlgo,
+
+			SubjectKeyId: []byte{1, 2, 3, 4},
+			KeyUsage:     KeyUsageCertSign,
+
+			ExtKeyUsage:        testExtKeyUsage,
+			UnknownExtKeyUsage: testUnknownExtKeyUsage,
+
+			BasicConstraintsValid: true,
+			IsCA:                  true,
+
+			OCSPServer:            []string{"http://ocsp.example.com"},
+			IssuingCertificateURL: []string{"http://crt.example.com/ca1.crt"},
+
+			DNSNames:       []string{"test.example.com"},
+			EmailAddresses: []string{"gopher@golang.org"},
+			IPAddresses:    []net.IP{net.IPv4(127, 0, 0, 1).To4(), net.ParseIP("2001:4860:0:2001::68")},
+			URIs:           []*url.URL{parseURI("https://foo.com/wibble#foo")},
+
+			PolicyIdentifiers:       []asn1.ObjectIdentifier{[]int{1, 2, 3}},
+			PermittedDNSDomains:     []string{".example.com", "example.com"},
+			ExcludedDNSDomains:      []string{"bar.example.com"},
+			PermittedIPRanges:       []*net.IPNet{parseCIDR("192.168.1.1/16"), parseCIDR("1.2.3.4/8")},
+			ExcludedIPRanges:        []*net.IPNet{parseCIDR("2001:db8::/48")},
+			PermittedEmailAddresses: []string{"foo@example.com"},
+			ExcludedEmailAddresses:  []string{".example.com", "example.com"},
+			PermittedURIDomains:     []string{".bar.com", "bar.com"},
+			ExcludedURIDomains:      []string{".bar2.com", "bar2.com"},
+
+			CRLDistributionPoints: []string{"http://crl1.example.com/ca1.crl", "http://crl2.example.com/ca1.crl"},
+
+			ExtraExtensions: []pkix.Extension{
+				{
+					Id:    []int{1, 2, 3, 4},
+					Value: extraExtensionData,
+				},
+				// This extension should override the SubjectKeyId, above.
+				{
+					Id:       oidExtensionSubjectKeyId,
+					Critical: false,
+					Value:    []byte{0x04, 0x04, 4, 3, 2, 1},
+				},
+			},
+		}
+
+		derBytes, err := CreateCertificate(random, &template, &template, test.pub, test.priv)
+		if err != nil {
+			t.Errorf("%s: failed to create certificate: %s", test.name, err)
+			continue
+		}
+
+		cert, err := ParseCertificate(derBytes)
+		if err != nil {
+			t.Errorf("%s: failed to parse certificate: %s", test.name, err)
+			continue
+		}
+
+		if len(cert.PolicyIdentifiers) != 1 || !cert.PolicyIdentifiers[0].Equal(template.PolicyIdentifiers[0]) {
+			t.Errorf("%s: failed to parse policy identifiers: got:%#v want:%#v", test.name, cert.PolicyIdentifiers, template.PolicyIdentifiers)
+		}
+
+		if len(cert.PermittedDNSDomains) != 2 || cert.PermittedDNSDomains[0] != ".example.com" || cert.PermittedDNSDomains[1] != "example.com" {
+			t.Errorf("%s: failed to parse name constraints: %#v", test.name, cert.PermittedDNSDomains)
+		}
+
+		if len(cert.ExcludedDNSDomains) != 1 || cert.ExcludedDNSDomains[0] != "bar.example.com" {
+			t.Errorf("%s: failed to parse name constraint exclusions: %#v", test.name, cert.ExcludedDNSDomains)
+		}
+
+		if len(cert.PermittedIPRanges) != 2 || cert.PermittedIPRanges[0].String() != "192.168.0.0/16" || cert.PermittedIPRanges[1].String() != "1.0.0.0/8" {
+			t.Errorf("%s: failed to parse IP constraints: %#v", test.name, cert.PermittedIPRanges)
+		}
+
+		if len(cert.ExcludedIPRanges) != 1 || cert.ExcludedIPRanges[0].String() != "2001:db8::/48" {
+			t.Errorf("%s: failed to parse IP constraint exclusions: %#v", test.name, cert.ExcludedIPRanges)
+		}
+
+		if len(cert.PermittedEmailAddresses) != 1 || cert.PermittedEmailAddresses[0] != "foo@example.com" {
+			t.Errorf("%s: failed to parse permitted email addresses: %#v", test.name, cert.PermittedEmailAddresses)
+		}
+
+		if len(cert.ExcludedEmailAddresses) != 2 || cert.ExcludedEmailAddresses[0] != ".example.com" || cert.ExcludedEmailAddresses[1] != "example.com" {
+			t.Errorf("%s: failed to parse excluded email addresses: %#v", test.name, cert.ExcludedEmailAddresses)
+		}
+
+		if len(cert.PermittedURIDomains) != 2 || cert.PermittedURIDomains[0] != ".bar.com" || cert.PermittedURIDomains[1] != "bar.com" {
+			t.Errorf("%s: failed to parse permitted URIs: %#v", test.name, cert.PermittedURIDomains)
+		}
+
+		if len(cert.ExcludedURIDomains) != 2 || cert.ExcludedURIDomains[0] != ".bar2.com" || cert.ExcludedURIDomains[1] != "bar2.com" {
+			t.Errorf("%s: failed to parse excluded URIs: %#v", test.name, cert.ExcludedURIDomains)
+		}
+
+		if cert.Subject.CommonName != commonName {
+			t.Errorf("%s: subject wasn't correctly copied from the template. Got %s, want %s", test.name, cert.Subject.CommonName, commonName)
+		}
+
+		if len(cert.Subject.Country) != 1 || cert.Subject.Country[0] != "NL" {
+			t.Errorf("%s: ExtraNames didn't override Country", test.name)
+		}
+
+		for _, ext := range cert.Extensions {
+			if ext.Id.Equal(oidExtensionSubjectAltName) {
+				if ext.Critical {
+					t.Fatal("SAN extension is marked critical")
+				}
+			}
+		}
+
+		found := false
+		for _, atv := range cert.Subject.Names {
+			if atv.Type.Equal([]int{2, 5, 4, 42}) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Errorf("%s: Names didn't contain oid 2.5.4.42 from ExtraNames", test.name)
+		}
+
+		if cert.Issuer.CommonName != commonName {
+			t.Errorf("%s: issuer wasn't correctly copied from the template. Got %s, want %s", test.name, cert.Issuer.CommonName, commonName)
+		}
+
+		if cert.SignatureAlgorithm != test.sigAlgo {
+			t.Errorf("%s: SignatureAlgorithm wasn't copied from template. Got %v, want %v", test.name, cert.SignatureAlgorithm, test.sigAlgo)
+		}
+
+		if !reflect.DeepEqual(cert.ExtKeyUsage, testExtKeyUsage) {
+			t.Errorf("%s: extkeyusage wasn't correctly copied from the template. Got %v, want %v", test.name, cert.ExtKeyUsage, testExtKeyUsage)
+		}
+
+		if !reflect.DeepEqual(cert.UnknownExtKeyUsage, testUnknownExtKeyUsage) {
+			t.Errorf("%s: unknown extkeyusage wasn't correctly copied from the template. Got %v, want %v", test.name, cert.UnknownExtKeyUsage, testUnknownExtKeyUsage)
+		}
+
+		if !reflect.DeepEqual(cert.OCSPServer, template.OCSPServer) {
+			t.Errorf("%s: OCSP servers differ from template. Got %v, want %v", test.name, cert.OCSPServer, template.OCSPServer)
+		}
+
+		if !reflect.DeepEqual(cert.IssuingCertificateURL, template.IssuingCertificateURL) {
+			t.Errorf("%s: Issuing certificate URLs differ from template. Got %v, want %v", test.name, cert.IssuingCertificateURL, template.IssuingCertificateURL)
+		}
+
+		if !reflect.DeepEqual(cert.DNSNames, template.DNSNames) {
+			t.Errorf("%s: SAN DNS names differ from template. Got %v, want %v", test.name, cert.DNSNames, template.DNSNames)
+		}
+
+		if !reflect.DeepEqual(cert.EmailAddresses, template.EmailAddresses) {
+			t.Errorf("%s: SAN emails differ from template. Got %v, want %v", test.name, cert.EmailAddresses, template.EmailAddresses)
+		}
+
+		if len(cert.URIs) != 1 || cert.URIs[0].String() != "https://foo.com/wibble#foo" {
+			t.Errorf("%s: URIs differ from template. Got %v, want %v", test.name, cert.URIs, template.URIs)
+		}
+
+		if !reflect.DeepEqual(cert.IPAddresses, template.IPAddresses) {
+			t.Errorf("%s: SAN IPs differ from template. Got %v, want %v", test.name, cert.IPAddresses, template.IPAddresses)
+		}
+
+		if !reflect.DeepEqual(cert.CRLDistributionPoints, template.CRLDistributionPoints) {
+			t.Errorf("%s: CRL distribution points differ from template. Got %v, want %v", test.name, cert.CRLDistributionPoints, template.CRLDistributionPoints)
+		}
+
+		if !bytes.Equal(cert.SubjectKeyId, []byte{4, 3, 2, 1}) {
+			t.Errorf("%s: ExtraExtensions didn't override SubjectKeyId", test.name)
+		}
+
+		if !bytes.Contains(derBytes, extraExtensionData) {
+			t.Errorf("%s: didn't find extra extension in DER output", test.name)
+		}
+
+		if test.checkSig {
+			err = cert.CheckSignatureFrom(cert)
+			if err != nil {
+				t.Errorf("%s: signature verification failed: %s", test.name, err)
+			}
+		}
+	}
+}
+
+// Self-signed certificate using ECDSA with SHA1 & secp256r1
+var ecdsaSHA1CertPem = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+// Self-signed certificate using ECDSA with SHA256 & secp256r1
+var ecdsaSHA256p256CertPem = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+// Self-signed certificate using ECDSA with SHA256 & secp384r1
+var ecdsaSHA256p384CertPem = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+// Self-signed certificate using ECDSA with SHA384 & secp521r1
+var ecdsaSHA384p521CertPem = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+var ecdsaTests = []struct {
+	sigAlgo SignatureAlgorithm
+	pemCert string
+}{
+	{ECDSAWithSHA256, ecdsaSHA256p256CertPem},
+	{ECDSAWithSHA256, ecdsaSHA256p384CertPem},
+	{ECDSAWithSHA384, ecdsaSHA384p521CertPem},
+}
+
+func TestECDSA(t *testing.T) {
+	for i, test := range ecdsaTests {
+		pemBlock, _ := pem.Decode([]byte(test.pemCert))
+		cert, err := ParseCertificate(pemBlock.Bytes)
+		if err != nil {
+			t.Errorf("%d: failed to parse certificate: %s", i, err)
+			continue
+		}
+		if sa := cert.SignatureAlgorithm; sa != test.sigAlgo {
+			t.Errorf("%d: signature algorithm is %v, want %v", i, sa, test.sigAlgo)
+		}
+		if parsedKey, ok := cert.PublicKey.(*ecdsa.PublicKey); !ok {
+			t.Errorf("%d: wanted an ECDSA public key but found: %#v", i, parsedKey)
+		}
+		if pka := cert.PublicKeyAlgorithm; pka != ECDSA {
+			t.Errorf("%d: public key algorithm is %v, want ECDSA", i, pka)
+		}
+		if err = cert.CheckSignatureFrom(cert); err != nil {
+			t.Errorf("%d: certificate verification failed: %s", i, err)
+		}
+	}
+}
+
+// Self-signed certificate using DSA with SHA1
+var dsaCertPem = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+func TestParseCertificateWithDsaPublicKey(t *testing.T) {
+	expectedKey := &dsa.PublicKey{
+		Parameters: dsa.Parameters{
+			P: bigFromHexString("00BC84B52743B169158BB85974E3E832AF5EFCFC42B264349095313A4A013EEE069A1B937D92E51ACF297A1C77880DF25C8607D8204B4DC45651305EF4A63B40C7D8C42D91EDA397D8F51CBC9D0A531FE2C6F1E55E9357D205C39D395358968CBEDAC11320C607BE16CB9DB492B6E78163305A34DD99CE43C64927D13A0040EB97"),
+			Q: bigFromHexString("009A67067F66A323F5D4EC7902C73FE5D9E36FA74F"),
+			G: bigFromHexString("009147778295BF5893542BC41BA806898A29E43261DBC85441C37D92E97ED80D323D44825FDDE8374D0FF15877798812682599B216BBCC31B9DCCAD527465FEAFFD7FC2A193612E575E34E7A98AF4D10339FE47390A518CB9975B3160B1D0285D1418D0977C52994F43C29A053E3D685834104C9FAFDC221E38BE9F3989D7A8E42"),
+		},
+		Y: bigFromHexString("59A27C269FCDE45AA2160A5C980C19211A820095091AB9C5DC8309AB7EC1B3A48C2E267C6D35FEE9B71BCBB92F16AC8E559129347FB5C00BEEDD10BA8915C90698755CA965735A32DC7575BED806E1E38F768FFBC24E41123DC73F1C6E9E4D0C9E692128853AFE29DC665FA993DCA9C903B7BF00B6442B9A76A5DADC6186317A"),
+	}
+	pemBlock, _ := pem.Decode([]byte(dsaCertPem))
+	cert, err := ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		t.Fatalf("Failed to parse certificate: %s", err)
+	}
+	if cert.PublicKeyAlgorithm != DSA {
+		t.Errorf("Parsed key algorithm was not DSA")
+	}
+	parsedKey, ok := cert.PublicKey.(*dsa.PublicKey)
+	if !ok {
+		t.Fatalf("Parsed key was not a DSA key: %s", err)
+	}
+	if expectedKey.Y.Cmp(parsedKey.Y) != 0 ||
+		expectedKey.P.Cmp(parsedKey.P) != 0 ||
+		expectedKey.Q.Cmp(parsedKey.Q) != 0 ||
+		expectedKey.G.Cmp(parsedKey.G) != 0 {
+		t.Fatal("Parsed key differs from expected key")
+	}
+}
+
+func TestParseCertificateWithDSASignatureAlgorithm(t *testing.T) {
+	pemBlock, _ := pem.Decode([]byte(dsaCertPem))
+	cert, err := ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		t.Fatalf("Failed to parse certificate: %s", err)
+	}
+	if cert.SignatureAlgorithm != DSAWithSHA1 {
+		t.Errorf("Parsed signature algorithm was not DSAWithSHA1")
+	}
+}
+
+func TestVerifyCertificateWithDSASignature(t *testing.T) {
+	pemBlock, _ := pem.Decode([]byte(dsaCertPem))
+	cert, err := ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		t.Fatalf("Failed to parse certificate: %s", err)
+	}
+	// test cert is self-signed
+	if err = cert.CheckSignatureFrom(cert); err == nil {
+		t.Fatalf("Expected error verifying DSA certificate")
+	}
+}
+
+var rsaPSSSelfSignedPEM = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+// openssl req -newkey rsa:2048 -keyout test.key -sha256 -sigopt \
+// rsa_padding_mode:pss -sigopt rsa_pss_saltlen:32 -sigopt rsa_mgf1_md:sha256 \
+// -x509 -days 3650 -nodes -subj '/C=US/ST=CA/L=SF/O=Test/CN=Test' -out \
+// test.pem
+var rsaPSSSelfSignedOpenSSL110PEM = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestRSAPSSSelfSigned(t *testing.T) {
+	for i, pemBlock := range []string{rsaPSSSelfSignedPEM, rsaPSSSelfSignedOpenSSL110PEM} {
+		der, _ := pem.Decode([]byte(pemBlock))
+		if der == nil {
+			t.Errorf("#%d: failed to find PEM block", i)
+			continue
+		}
+
+		cert, err := ParseCertificate(der.Bytes)
+		if err != nil {
+			t.Errorf("#%d: failed to parse: %s", i, err)
+			continue
+		}
+
+		if err = cert.CheckSignatureFrom(cert); err != nil {
+			t.Errorf("#%d: signature check failed: %s", i, err)
+			continue
+		}
+	}
+}
+
+const ed25519Certificate = `
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number:
+            0c:83:d8:21:2b:82:cb:23:98:23:63:e2:f7:97:8a:43:5b:f3:bd:92
+        Signature Algorithm: ED25519
+        Issuer: CN = Ed25519 test certificate
+        Validity
+            Not Before: May  6 17:27:16 2019 GMT
+            Not After : Jun  5 17:27:16 2019 GMT
+        Subject: CN = Ed25519 test certificate
+        Subject Public Key Info:
+            Public Key Algorithm: ED25519
+                ED25519 Public-Key:
+                pub:
+                    36:29:c5:6c:0d:4f:14:6c:81:d0:ff:75:d3:6a:70:
+                    5f:69:cd:0f:4d:66:d5:da:98:7e:82:49:89:a3:8a:
+                    3c:fa
+        X509v3 extensions:
+            X509v3 Subject Key Identifier:
+                09:3B:3A:9D:4A:29:D8:95:FF:68:BE:7B:43:54:72:E0:AD:A2:E3:AE
+            X509v3 Authority Key Identifier:
+                keyid:09:3B:3A:9D:4A:29:D8:95:FF:68:BE:7B:43:54:72:E0:AD:A2:E3:AE
+
+            X509v3 Basic Constraints: critical
+                CA:TRUE
+    Signature Algorithm: ED25519
+         53:a5:58:1c:2c:3b:2a:9e:ac:9d:4e:a5:1d:5f:5d:6d:a6:b5:
+         08:de:12:82:f3:97:20:ae:fa:d8:98:f4:1a:83:32:6b:91:f5:
+         24:1d:c4:20:7f:2c:e2:4d:da:13:3b:6d:54:1a:d2:a8:28:dc:
+         60:b9:d4:f4:78:4b:3c:1c:91:00
+-----BEGIN CERTIFICATE-----
+MIIBWzCCAQ2gAwIBAgIUDIPYISuCyyOYI2Pi95eKQ1vzvZIwBQYDK2VwMCMxITAf
+BgNVBAMMGEVkMjU1MTkgdGVzdCBjZXJ0aWZpY2F0ZTAeFw0xOTA1MDYxNzI3MTZa
+Fw0xOTA2MDUxNzI3MTZaMCMxITAfBgNVBAMMGEVkMjU1MTkgdGVzdCBjZXJ0aWZp
+Y2F0ZTAqMAUGAytlcAMhADYpxWwNTxRsgdD/ddNqcF9pzQ9NZtXamH6CSYmjijz6
+o1MwUTAdBgNVHQ4EFgQUCTs6nUop2JX/aL57Q1Ry4K2i464wHwYDVR0jBBgwFoAU
+CTs6nUop2JX/aL57Q1Ry4K2i464wDwYDVR0TAQH/BAUwAwEB/zAFBgMrZXADQQBT
+pVgcLDsqnqydTqUdX11tprUI3hKC85cgrvrYmPQagzJrkfUkHcQgfyziTdoTO21U
+GtKoKNxgudT0eEs8HJEA
+-----END CERTIFICATE-----`
+
+func TestEd25519SelfSigned(t *testing.T) {
+	der, _ := pem.Decode([]byte(ed25519Certificate))
+	if der == nil {
+		t.Fatalf("Failed to find PEM block")
+	}
+
+	cert, err := ParseCertificate(der.Bytes)
+	if err != nil {
+		t.Fatalf("Failed to parse: %s", err)
+	}
+
+	if cert.PublicKeyAlgorithm != Ed25519 {
+		t.Fatalf("Parsed key algorithm was not Ed25519")
+	}
+	parsedKey, ok := cert.PublicKey.(ed25519.PublicKey)
+	if !ok {
+		t.Fatalf("Parsed key was not an Ed25519 key: %s", err)
+	}
+	if len(parsedKey) != ed25519.PublicKeySize {
+		t.Fatalf("Invalid Ed25519 key")
+	}
+
+	if err = cert.CheckSignatureFrom(cert); err != nil {
+		t.Fatalf("Signature check failed: %s", err)
+	}
+}
+
+const pemCertificate = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+const ed25519CRLCertificate = `
+Certificate:
+Data:
+	Version: 3 (0x2)
+	Serial Number:
+		7a:07:a0:9d:14:04:16:fc:1f:d8:e5:fe:d1:1d:1f:8d
+	Signature Algorithm: ED25519
+	Issuer: CN = Ed25519 CRL Test CA
+	Validity
+		Not Before: Oct 30 01:20:20 2019 GMT
+		Not After : Dec 31 23:59:59 9999 GMT
+	Subject: CN = Ed25519 CRL Test CA
+	Subject Public Key Info:
+		Public Key Algorithm: ED25519
+			ED25519 Public-Key:
+			pub:
+				95:73:3b:b0:06:2a:31:5a:b6:a7:a6:6e:ef:71:df:
+				ac:6f:6b:39:03:85:5e:63:4b:f8:a6:0f:68:c6:6f:
+				75:21
+	X509v3 extensions:
+		X509v3 Key Usage: critical
+			Digital Signature, Certificate Sign, CRL Sign
+		X509v3 Extended Key Usage:
+			TLS Web Client Authentication, TLS Web Server Authentication, OCSP Signing
+		X509v3 Basic Constraints: critical
+			CA:TRUE
+		X509v3 Subject Key Identifier:
+			B7:17:DA:16:EA:C5:ED:1F:18:49:44:D3:D2:E3:A0:35:0A:81:93:60
+		X509v3 Authority Key Identifier:
+			keyid:B7:17:DA:16:EA:C5:ED:1F:18:49:44:D3:D2:E3:A0:35:0A:81:93:60
+
+Signature Algorithm: ED25519
+	 fc:3e:14:ea:bb:70:c2:6f:38:34:70:bc:c8:a7:f4:7c:0d:1e:
+	 28:d7:2a:9f:22:8a:45:e8:02:76:84:1e:2d:64:2d:1e:09:b5:
+	 29:71:1f:95:8a:4e:79:87:51:60:9a:e7:86:40:f6:60:c7:d1:
+	 ee:68:76:17:1d:90:cc:92:93:07
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+var ed25519CRLKey = testingKey(`-----BEGIN TEST KEY-----
+MC4CAQAwBQYDK2VwBCIEINdKh2096vUBYu4EIFpjShsUSh3vimKya1sQ1YTT4RZG
+-----END TEST KEY-----`)
+
+func TestCRLCreation(t *testing.T) {
+	block, _ := pem.Decode([]byte(pemPrivateKey))
+	privRSA, _ := ParsePKCS1PrivateKey(block.Bytes)
+	block, _ = pem.Decode([]byte(pemCertificate))
+	certRSA, _ := ParseCertificate(block.Bytes)
+
+	block, _ = pem.Decode([]byte(ed25519CRLKey))
+	privEd25519, _ := ParsePKCS8PrivateKey(block.Bytes)
+	block, _ = pem.Decode([]byte(ed25519CRLCertificate))
+	certEd25519, _ := ParseCertificate(block.Bytes)
+
+	tests := []struct {
+		name string
+		priv any
+		cert *Certificate
+	}{
+		{"RSA CA", privRSA, certRSA},
+		{"Ed25519 CA", privEd25519, certEd25519},
+	}
+
+	loc := time.FixedZone("Oz/Atlantis", int((2 * time.Hour).Seconds()))
+
+	now := time.Unix(1000, 0).In(loc)
+	nowUTC := now.UTC()
+	expiry := time.Unix(10000, 0)
+
+	revokedCerts := []pkix.RevokedCertificate{
+		{
+			SerialNumber:   big.NewInt(1),
+			RevocationTime: nowUTC,
+		},
+		{
+			SerialNumber: big.NewInt(42),
+			// RevocationTime should be converted to UTC before marshaling.
+			RevocationTime: now,
+		},
+	}
+	expectedCerts := []pkix.RevokedCertificate{
+		{
+			SerialNumber:   big.NewInt(1),
+			RevocationTime: nowUTC,
+		},
+		{
+			SerialNumber:   big.NewInt(42),
+			RevocationTime: nowUTC,
+		},
+	}
+
+	for _, test := range tests {
+		crlBytes, err := test.cert.CreateCRL(rand.Reader, test.priv, revokedCerts, now, expiry)
+		if err != nil {
+			t.Errorf("%s: error creating CRL: %s", test.name, err)
+		}
+
+		parsedCRL, err := ParseDERCRL(crlBytes)
+		if err != nil {
+			t.Errorf("%s: error reparsing CRL: %s", test.name, err)
+		}
+		if !reflect.DeepEqual(parsedCRL.TBSCertList.RevokedCertificates, expectedCerts) {
+			t.Errorf("%s: RevokedCertificates mismatch: got %v; want %v.", test.name,
+				parsedCRL.TBSCertList.RevokedCertificates, expectedCerts)
+		}
+	}
+}
+
+func fromBase64(in string) []byte {
+	out := make([]byte, base64.StdEncoding.DecodedLen(len(in)))
+	n, err := base64.StdEncoding.Decode(out, []byte(in))
+	if err != nil {
+		panic("failed to base64 decode")
+	}
+	return out[:n]
+}
+
+func TestParseDERCRL(t *testing.T) {
+	derBytes := fromBase64(derCRLBase64)
+	certList, err := ParseDERCRL(derBytes)
+	if err != nil {
+		t.Errorf("error parsing: %s", err)
+		return
+	}
+	numCerts := len(certList.TBSCertList.RevokedCertificates)
+	expected := 88
+	if numCerts != expected {
+		t.Errorf("bad number of revoked certificates. got: %d want: %d", numCerts, expected)
+	}
+
+	if certList.HasExpired(time.Unix(1302517272, 0)) {
+		t.Errorf("CRL has expired (but shouldn't have)")
+	}
+
+	// Can't check the signature here without a package cycle.
+}
+
+func TestCRLWithoutExpiry(t *testing.T) {
+	derBytes := fromBase64("MIHYMIGZMAkGByqGSM44BAMwEjEQMA4GA1UEAxMHQ2FybERTUxcNOTkwODI3MDcwMDAwWjBpMBMCAgDIFw05OTA4MjIwNzAwMDBaMBMCAgDJFw05OTA4MjIwNzAwMDBaMBMCAgDTFw05OTA4MjIwNzAwMDBaMBMCAgDSFw05OTA4MjIwNzAwMDBaMBMCAgDUFw05OTA4MjQwNzAwMDBaMAkGByqGSM44BAMDLwAwLAIUfmVSdjP+NHMX0feW+aDU2G1cfT0CFAJ6W7fVWxjBz4fvftok8yqDnDWh")
+	certList, err := ParseDERCRL(derBytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !certList.TBSCertList.NextUpdate.IsZero() {
+		t.Errorf("NextUpdate is not the zero value")
+	}
+}
+
+func TestParsePEMCRL(t *testing.T) {
+	pemBytes := fromBase64(pemCRLBase64)
+	certList, err := ParseCRL(pemBytes)
+	if err != nil {
+		t.Errorf("error parsing: %s", err)
+		return
+	}
+	numCerts := len(certList.TBSCertList.RevokedCertificates)
+	expected := 2
+	if numCerts != expected {
+		t.Errorf("bad number of revoked certificates. got: %d want: %d", numCerts, expected)
+	}
+
+	if certList.HasExpired(time.Unix(1302517272, 0)) {
+		t.Errorf("CRL has expired (but shouldn't have)")
+	}
+
+	// Can't check the signature here without a package cycle.
+}
+
+func TestImports(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in -short mode")
+	}
+	testenv.MustHaveGoRun(t)
+
+	if out, err := exec.Command(testenv.GoToolPath(t), "run", "x509_test_import.go").CombinedOutput(); err != nil {
+		t.Errorf("failed to run x509_test_import.go: %s\n%s", err, out)
+	}
+}
+
+const derCRLBase64 = "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"
+
+const pemCRLBase64 = "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"
+
+func TestCreateCertificateRequest(t *testing.T) {
+	random := rand.Reader
+
+	ecdsa256Priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatalf("Failed to generate ECDSA key: %s", err)
+	}
+
+	ecdsa384Priv, err := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
+	if err != nil {
+		t.Fatalf("Failed to generate ECDSA key: %s", err)
+	}
+
+	ecdsa521Priv, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader)
+	if err != nil {
+		t.Fatalf("Failed to generate ECDSA key: %s", err)
+	}
+
+	_, ed25519Priv, err := ed25519.GenerateKey(random)
+	if err != nil {
+		t.Fatalf("Failed to generate Ed25519 key: %s", err)
+	}
+
+	tests := []struct {
+		name    string
+		priv    any
+		sigAlgo SignatureAlgorithm
+	}{
+		{"RSA", testPrivateKey, SHA256WithRSA},
+		{"ECDSA-256", ecdsa256Priv, ECDSAWithSHA256},
+		{"ECDSA-384", ecdsa384Priv, ECDSAWithSHA256},
+		{"ECDSA-521", ecdsa521Priv, ECDSAWithSHA256},
+		{"Ed25519", ed25519Priv, PureEd25519},
+	}
+
+	for _, test := range tests {
+		template := CertificateRequest{
+			Subject: pkix.Name{
+				CommonName:   "test.example.com",
+				Organization: []string{"Σ Acme Co"},
+			},
+			SignatureAlgorithm: test.sigAlgo,
+			DNSNames:           []string{"test.example.com"},
+			EmailAddresses:     []string{"gopher@golang.org"},
+			IPAddresses:        []net.IP{net.IPv4(127, 0, 0, 1).To4(), net.ParseIP("2001:4860:0:2001::68")},
+		}
+
+		derBytes, err := CreateCertificateRequest(random, &template, test.priv)
+		if err != nil {
+			t.Errorf("%s: failed to create certificate request: %s", test.name, err)
+			continue
+		}
+
+		out, err := ParseCertificateRequest(derBytes)
+		if err != nil {
+			t.Errorf("%s: failed to create certificate request: %s", test.name, err)
+			continue
+		}
+
+		err = out.CheckSignature()
+		if err != nil {
+			t.Errorf("%s: failed to check certificate request signature: %s", test.name, err)
+			continue
+		}
+
+		if out.Subject.CommonName != template.Subject.CommonName {
+			t.Errorf("%s: output subject common name and template subject common name don't match", test.name)
+		} else if len(out.Subject.Organization) != len(template.Subject.Organization) {
+			t.Errorf("%s: output subject organisation and template subject organisation don't match", test.name)
+		} else if len(out.DNSNames) != len(template.DNSNames) {
+			t.Errorf("%s: output DNS names and template DNS names don't match", test.name)
+		} else if len(out.EmailAddresses) != len(template.EmailAddresses) {
+			t.Errorf("%s: output email addresses and template email addresses don't match", test.name)
+		} else if len(out.IPAddresses) != len(template.IPAddresses) {
+			t.Errorf("%s: output IP addresses and template IP addresses names don't match", test.name)
+		}
+	}
+}
+
+func marshalAndParseCSR(t *testing.T, template *CertificateRequest) *CertificateRequest {
+	derBytes, err := CreateCertificateRequest(rand.Reader, template, testPrivateKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	csr, err := ParseCertificateRequest(derBytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return csr
+}
+
+func TestCertificateRequestOverrides(t *testing.T) {
+	sanContents, err := marshalSANs([]string{"foo.example.com"}, nil, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	template := CertificateRequest{
+		Subject: pkix.Name{
+			CommonName:   "test.example.com",
+			Organization: []string{"Σ Acme Co"},
+		},
+		DNSNames: []string{"test.example.com"},
+
+		// An explicit extension should override the DNSNames from the
+		// template.
+		ExtraExtensions: []pkix.Extension{
+			{
+				Id:       oidExtensionSubjectAltName,
+				Value:    sanContents,
+				Critical: true,
+			},
+		},
+	}
+
+	csr := marshalAndParseCSR(t, &template)
+
+	if len(csr.DNSNames) != 1 || csr.DNSNames[0] != "foo.example.com" {
+		t.Errorf("Extension did not override template. Got %v\n", csr.DNSNames)
+	}
+
+	if len(csr.Extensions) != 1 || !csr.Extensions[0].Id.Equal(oidExtensionSubjectAltName) || !csr.Extensions[0].Critical {
+		t.Errorf("SAN extension was not faithfully copied, got %#v", csr.Extensions)
+	}
+
+	// If there is already an attribute with X.509 extensions then the
+	// extra extensions should be added to it rather than creating a CSR
+	// with two extension attributes.
+
+	template.Attributes = []pkix.AttributeTypeAndValueSET{
+		{
+			Type: oidExtensionRequest,
+			Value: [][]pkix.AttributeTypeAndValue{
+				{
+					{
+						Type:  oidExtensionAuthorityInfoAccess,
+						Value: []byte("foo"),
+					},
+				},
+			},
+		},
+	}
+
+	csr = marshalAndParseCSR(t, &template)
+	if l := len(csr.Attributes); l != 1 {
+		t.Errorf("incorrect number of attributes: %d\n", l)
+	}
+
+	if !csr.Attributes[0].Type.Equal(oidExtensionRequest) ||
+		len(csr.Attributes[0].Value) != 1 ||
+		len(csr.Attributes[0].Value[0]) != 2 {
+		t.Errorf("bad attributes: %#v\n", csr.Attributes)
+	}
+
+	sanContents2, err := marshalSANs([]string{"foo2.example.com"}, nil, nil, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Extensions in Attributes should override those in ExtraExtensions.
+	template.Attributes[0].Value[0] = append(template.Attributes[0].Value[0], pkix.AttributeTypeAndValue{
+		Type:  oidExtensionSubjectAltName,
+		Value: sanContents2,
+	})
+
+	csr = marshalAndParseCSR(t, &template)
+
+	if len(csr.DNSNames) != 1 || csr.DNSNames[0] != "foo2.example.com" {
+		t.Errorf("Attributes did not override ExtraExtensions. Got %v\n", csr.DNSNames)
+	}
+}
+
+func TestParseCertificateRequest(t *testing.T) {
+	for _, csrBase64 := range csrBase64Array {
+		csrBytes := fromBase64(csrBase64)
+		csr, err := ParseCertificateRequest(csrBytes)
+		if err != nil {
+			t.Fatalf("failed to parse CSR: %s", err)
+		}
+
+		if len(csr.EmailAddresses) != 1 || csr.EmailAddresses[0] != "gopher@golang.org" {
+			t.Errorf("incorrect email addresses found: %v", csr.EmailAddresses)
+		}
+
+		if len(csr.DNSNames) != 1 || csr.DNSNames[0] != "test.example.com" {
+			t.Errorf("incorrect DNS names found: %v", csr.DNSNames)
+		}
+
+		if len(csr.Subject.Country) != 1 || csr.Subject.Country[0] != "AU" {
+			t.Errorf("incorrect Subject name: %v", csr.Subject)
+		}
+
+		found := false
+		for _, e := range csr.Extensions {
+			if e.Id.Equal(oidExtensionBasicConstraints) {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Errorf("basic constraints extension not found in CSR")
+		}
+	}
+}
+
+func TestCriticalFlagInCSRRequestedExtensions(t *testing.T) {
+	// This CSR contains an extension request where the extensions have a
+	// critical flag in them. In the past we failed to handle this.
+	const csrBase64 = "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"
+
+	csrBytes := fromBase64(csrBase64)
+	csr, err := ParseCertificateRequest(csrBytes)
+	if err != nil {
+		t.Fatalf("failed to parse CSR: %s", err)
+	}
+
+	expected := []struct {
+		Id    asn1.ObjectIdentifier
+		Value []byte
+	}{
+		{oidExtensionBasicConstraints, fromBase64("MAYBAf8CAQA=")},
+		{oidExtensionKeyUsage, fromBase64("AwIChA==")},
+	}
+
+	if n := len(csr.Extensions); n != len(expected) {
+		t.Fatalf("expected to find %d extensions but found %d", len(expected), n)
+	}
+
+	for i, extension := range csr.Extensions {
+		if !extension.Id.Equal(expected[i].Id) {
+			t.Fatalf("extension #%d has unexpected type %v (expected %v)", i, extension.Id, expected[i].Id)
+		}
+
+		if !bytes.Equal(extension.Value, expected[i].Value) {
+			t.Fatalf("extension #%d has unexpected contents %x (expected %x)", i, extension.Value, expected[i].Value)
+		}
+	}
+}
+
+// serialiseAndParse generates a self-signed certificate from template and
+// returns a parsed version of it.
+func serialiseAndParse(t *testing.T, template *Certificate) *Certificate {
+	derBytes, err := CreateCertificate(rand.Reader, template, template, &testPrivateKey.PublicKey, testPrivateKey)
+	if err != nil {
+		t.Fatalf("failed to create certificate: %s", err)
+		return nil
+	}
+
+	cert, err := ParseCertificate(derBytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+		return nil
+	}
+
+	return cert
+}
+
+func TestMaxPathLenNotCA(t *testing.T) {
+	template := &Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "Σ Acme Co",
+		},
+		NotBefore: time.Unix(1000, 0),
+		NotAfter:  time.Unix(100000, 0),
+
+		BasicConstraintsValid: true,
+		IsCA:                  false,
+	}
+	if m := serialiseAndParse(t, template).MaxPathLen; m != -1 {
+		t.Errorf("MaxPathLen should be -1 when IsCa is false, got %d", m)
+	}
+
+	template.MaxPathLen = -1
+	if m := serialiseAndParse(t, template).MaxPathLen; m != -1 {
+		t.Errorf("MaxPathLen should be -1 when IsCa is false and MaxPathLen set to -1, got %d", m)
+	}
+
+	template.MaxPathLen = 5
+	if _, err := CreateCertificate(rand.Reader, template, template, &testPrivateKey.PublicKey, testPrivateKey); err == nil {
+		t.Error("specifying a MaxPathLen when IsCA is false should fail")
+	}
+
+	template.MaxPathLen = 0
+	template.MaxPathLenZero = true
+	if _, err := CreateCertificate(rand.Reader, template, template, &testPrivateKey.PublicKey, testPrivateKey); err == nil {
+		t.Error("setting MaxPathLenZero when IsCA is false should fail")
+	}
+
+	template.BasicConstraintsValid = false
+	if m := serialiseAndParse(t, template).MaxPathLen; m != 0 {
+		t.Errorf("Bad MaxPathLen should be ignored if BasicConstraintsValid is false, got %d", m)
+	}
+}
+
+func TestMaxPathLen(t *testing.T) {
+	template := &Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "Σ Acme Co",
+		},
+		NotBefore: time.Unix(1000, 0),
+		NotAfter:  time.Unix(100000, 0),
+
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+	}
+
+	cert1 := serialiseAndParse(t, template)
+	if m := cert1.MaxPathLen; m != -1 {
+		t.Errorf("Omitting MaxPathLen didn't turn into -1, got %d", m)
+	}
+	if cert1.MaxPathLenZero {
+		t.Errorf("Omitting MaxPathLen resulted in MaxPathLenZero")
+	}
+
+	template.MaxPathLen = 1
+	cert2 := serialiseAndParse(t, template)
+	if m := cert2.MaxPathLen; m != 1 {
+		t.Errorf("Setting MaxPathLen didn't work. Got %d but set 1", m)
+	}
+	if cert2.MaxPathLenZero {
+		t.Errorf("Setting MaxPathLen resulted in MaxPathLenZero")
+	}
+
+	template.MaxPathLen = 0
+	template.MaxPathLenZero = true
+	cert3 := serialiseAndParse(t, template)
+	if m := cert3.MaxPathLen; m != 0 {
+		t.Errorf("Setting MaxPathLenZero didn't work, got %d", m)
+	}
+	if !cert3.MaxPathLenZero {
+		t.Errorf("Setting MaxPathLen to zero didn't result in MaxPathLenZero")
+	}
+}
+
+func TestNoAuthorityKeyIdInSelfSignedCert(t *testing.T) {
+	template := &Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "Σ Acme Co",
+		},
+		NotBefore: time.Unix(1000, 0),
+		NotAfter:  time.Unix(100000, 0),
+
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+		SubjectKeyId:          []byte{1, 2, 3, 4},
+	}
+
+	if cert := serialiseAndParse(t, template); len(cert.AuthorityKeyId) != 0 {
+		t.Fatalf("self-signed certificate contained default authority key id")
+	}
+
+	template.AuthorityKeyId = []byte{1, 2, 3, 4}
+	if cert := serialiseAndParse(t, template); len(cert.AuthorityKeyId) == 0 {
+		t.Fatalf("self-signed certificate erased explicit authority key id")
+	}
+}
+
+func TestNoSubjectKeyIdInCert(t *testing.T) {
+	template := &Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "Σ Acme Co",
+		},
+		NotBefore: time.Unix(1000, 0),
+		NotAfter:  time.Unix(100000, 0),
+
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+	}
+	if cert := serialiseAndParse(t, template); len(cert.SubjectKeyId) == 0 {
+		t.Fatalf("self-signed certificate did not generate subject key id using the public key")
+	}
+
+	template.IsCA = false
+	if cert := serialiseAndParse(t, template); len(cert.SubjectKeyId) != 0 {
+		t.Fatalf("self-signed certificate generated subject key id when it isn't a CA")
+	}
+
+	template.SubjectKeyId = []byte{1, 2, 3, 4}
+	if cert := serialiseAndParse(t, template); len(cert.SubjectKeyId) == 0 {
+		t.Fatalf("self-signed certificate erased explicit subject key id")
+	}
+}
+
+func TestASN1BitLength(t *testing.T) {
+	tests := []struct {
+		bytes  []byte
+		bitLen int
+	}{
+		{nil, 0},
+		{[]byte{0x00}, 0},
+		{[]byte{0x00, 0x00}, 0},
+		{[]byte{0xf0}, 4},
+		{[]byte{0x88}, 5},
+		{[]byte{0xff}, 8},
+		{[]byte{0xff, 0x80}, 9},
+		{[]byte{0xff, 0x81}, 16},
+	}
+
+	for i, test := range tests {
+		if got := asn1BitLength(test.bytes); got != test.bitLen {
+			t.Errorf("#%d: calculated bit-length of %d for %x, wanted %d", i, got, test.bytes, test.bitLen)
+		}
+	}
+}
+
+func TestVerifyEmptyCertificate(t *testing.T) {
+	if _, err := new(Certificate).Verify(VerifyOptions{}); err != errNotParsed {
+		t.Errorf("Verifying empty certificate resulted in unexpected error: %q (wanted %q)", err, errNotParsed)
+	}
+}
+
+func TestInsecureAlgorithmErrorString(t *testing.T) {
+	tests := []struct {
+		sa   SignatureAlgorithm
+		want string
+	}{
+		{MD5WithRSA, "x509: cannot verify signature: insecure algorithm MD5-RSA"},
+		{SHA1WithRSA, "x509: cannot verify signature: insecure algorithm SHA1-RSA (temporarily override with GODEBUG=x509sha1=1)"},
+		{ECDSAWithSHA1, "x509: cannot verify signature: insecure algorithm ECDSA-SHA1 (temporarily override with GODEBUG=x509sha1=1)"},
+		{MD2WithRSA, "x509: cannot verify signature: insecure algorithm MD2-RSA"},
+		{-1, "x509: cannot verify signature: insecure algorithm -1"},
+		{0, "x509: cannot verify signature: insecure algorithm 0"},
+		{9999, "x509: cannot verify signature: insecure algorithm 9999"},
+	}
+	for i, tt := range tests {
+		if got := fmt.Sprint(InsecureAlgorithmError(tt.sa)); got != tt.want {
+			t.Errorf("%d. mismatch.\n got: %s\nwant: %s\n", i, got, tt.want)
+		}
+	}
+}
+
+// These CSR was generated with OpenSSL:
+//
+//	openssl req -out CSR.csr -new -sha256 -nodes -keyout privateKey.key -config openssl.cnf
+//
+// With openssl.cnf containing the following sections:
+//
+//	[ v3_req ]
+//	basicConstraints = CA:FALSE
+//	keyUsage = nonRepudiation, digitalSignature, keyEncipherment
+//	subjectAltName = email:gopher@golang.org,DNS:test.example.com
+//	[ req_attributes ]
+//	challengePassword = ignored challenge
+//	unstructuredName  = ignored unstructured name
+var csrBase64Array = [...]string{
+	// Just [ v3_req ]
+	"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",
+	// Both [ v3_req ] and [ req_attributes ]
+	"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",
+}
+
+var md5cert = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+func TestMD5(t *testing.T) {
+	pemBlock, _ := pem.Decode([]byte(md5cert))
+	cert, err := ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+	if sa := cert.SignatureAlgorithm; sa != MD5WithRSA {
+		t.Errorf("signature algorithm is %v, want %v", sa, MD5WithRSA)
+	}
+	if err = cert.CheckSignatureFrom(cert); err == nil {
+		t.Fatalf("certificate verification succeeded incorrectly")
+	}
+	if _, ok := err.(InsecureAlgorithmError); !ok {
+		t.Fatalf("certificate verification returned %v (%T), wanted InsecureAlgorithmError", err, err)
+	}
+}
+
+func TestSHA1(t *testing.T) {
+	pemBlock, _ := pem.Decode([]byte(ecdsaSHA1CertPem))
+	cert, err := ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+	if sa := cert.SignatureAlgorithm; sa != ECDSAWithSHA1 {
+		t.Errorf("signature algorithm is %v, want %v", sa, ECDSAWithSHA1)
+	}
+	if err = cert.CheckSignatureFrom(cert); err == nil {
+		t.Fatalf("certificate verification succeeded incorrectly")
+	}
+	if _, ok := err.(InsecureAlgorithmError); !ok {
+		t.Fatalf("certificate verification returned %v (%T), wanted InsecureAlgorithmError", err, err)
+	}
+
+	t.Setenv("GODEBUG", "x509sha1=1")
+	if err = cert.CheckSignatureFrom(cert); err != nil {
+		t.Fatalf("SHA-1 certificate did not verify with GODEBUG=x509sha1=1: %v", err)
+	}
+}
+
+// certMissingRSANULL contains an RSA public key where the AlgorithmIdentifier
+// parameters are omitted rather than being an ASN.1 NULL.
+const certMissingRSANULL = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestRSAMissingNULLParameters(t *testing.T) {
+	block, _ := pem.Decode([]byte(certMissingRSANULL))
+	if _, err := ParseCertificate(block.Bytes); err == nil {
+		t.Error("unexpected success when parsing certificate with missing RSA NULL parameter")
+	} else if !strings.Contains(err.Error(), "missing NULL") {
+		t.Errorf("unrecognised error when parsing certificate with missing RSA NULL parameter: %s", err)
+	}
+}
+
+const certISOOID = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestISOOIDInCertificate(t *testing.T) {
+	block, _ := pem.Decode([]byte(certISOOID))
+	if cert, err := ParseCertificate(block.Bytes); err != nil {
+		t.Errorf("certificate with ISO OID failed to parse: %s", err)
+	} else if cert.SignatureAlgorithm == UnknownSignatureAlgorithm {
+		t.Errorf("ISO OID not recognised in certificate")
+	}
+}
+
+// certMultipleRDN contains a RelativeDistinguishedName with two elements (the
+// common name and serial number). This particular certificate was the first
+// such certificate in the “Pilot” Certificate Transparency log.
+const certMultipleRDN = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestMultipleRDN(t *testing.T) {
+	block, _ := pem.Decode([]byte(certMultipleRDN))
+	cert, err := ParseCertificate(block.Bytes)
+	if err != nil {
+		t.Fatalf("certificate with two elements in an RDN failed to parse: %v", err)
+	}
+
+	if want := "eportal.mss.edus.si"; cert.Subject.CommonName != want {
+		t.Errorf("got common name of %q, but want %q", cert.Subject.CommonName, want)
+	}
+
+	if want := "1236484010010"; cert.Subject.SerialNumber != want {
+		t.Errorf("got serial number of %q, but want %q", cert.Subject.SerialNumber, want)
+	}
+}
+
+func TestSystemCertPool(t *testing.T) {
+	if runtime.GOOS == "windows" || runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
+		t.Skip("not implemented on Windows (Issue 16736, 18609) or darwin (Issue 46287)")
+	}
+	a, err := SystemCertPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	b, err := SystemCertPool()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !certPoolEqual(a, b) {
+		t.Fatal("two calls to SystemCertPool had different results")
+	}
+	if ok := b.AppendCertsFromPEM([]byte(`
+-----BEGIN CERTIFICATE-----
+MIIDBjCCAe6gAwIBAgIRANXM5I3gjuqDfTp/PYrs+u8wDQYJKoZIhvcNAQELBQAw
+EjEQMA4GA1UEChMHQWNtZSBDbzAeFw0xODAzMjcxOTU2MjFaFw0xOTAzMjcxOTU2
+MjFaMBIxEDAOBgNVBAoTB0FjbWUgQ28wggEiMA0GCSqGSIb3DQEBAQUAA4IBDwAw
+ggEKAoIBAQDK+9m3rjsO2Djes6bIYQZ3eV29JF09ZrjOrEHLtaKrD6/acsoSoTsf
+cQr+rzzztdB5ijWXCS64zo/0OiqBeZUNZ67jVdToa9qW5UYe2H0Y+ZNdfA5GYMFD
+yk/l3/uBu3suTZPfXiW2TjEi27Q8ruNUIZ54DpTcs6y2rBRFzadPWwn/VQMlvRXM
+jrzl8Y08dgnYmaAHprxVzwMXcQ/Brol+v9GvjaH1DooHqkn8O178wsPQNhdtvN01
+IXL46cYdcUwWrE/GX5u+9DaSi+0KWxAPQ+NVD5qUI0CKl4714yGGh7feXMjJdHgl
+VG4QJZlJvC4FsURgCHJT6uHGIelnSwhbAgMBAAGjVzBVMA4GA1UdDwEB/wQEAwIF
+oDATBgNVHSUEDDAKBggrBgEFBQcDATAMBgNVHRMBAf8EAjAAMCAGA1UdEQQZMBeC
+FVRlc3RTeXN0ZW1DZXJ0UG9vbC5nbzANBgkqhkiG9w0BAQsFAAOCAQEAwuSRx/VR
+BKh2ICxZjL6jBwk/7UlU1XKbhQD96RqkidDNGEc6eLZ90Z5XXTurEsXqdm5jQYPs
+1cdcSW+fOSMl7MfW9e5tM66FaIPZl9rKZ1r7GkOfgn93xdLAWe8XHd19xRfDreub
+YC8DVqgLASOEYFupVSl76ktPfxkU5KCvmUf3P2PrRybk1qLGFytGxfyice2gHSNI
+gify3K/+H/7wCkyFW4xYvzl7WW4mXxoqPRPjQt1J423DhnnQ4G1P8V/vhUpXNXOq
+N9IEPnWuihC09cyx/WMQIUlWnaQLHdfpPS04Iez3yy2PdfXJzwfPrja7rNE+skK6
+pa/O1nF0AfWOpw==
+-----END CERTIFICATE-----
+	`)); !ok {
+		t.Fatal("AppendCertsFromPEM failed")
+	}
+	if reflect.DeepEqual(a, b) {
+		t.Fatal("changing one pool modified the other")
+	}
+}
+
+const emptyNameConstraintsPEM = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestEmptyNameConstraints(t *testing.T) {
+	block, _ := pem.Decode([]byte(emptyNameConstraintsPEM))
+	_, err := ParseCertificate(block.Bytes)
+	if err == nil {
+		t.Fatal("unexpected success")
+	}
+
+	const expected = "empty name constraints"
+	if str := err.Error(); !strings.Contains(str, expected) {
+		t.Errorf("expected %q in error but got %q", expected, str)
+	}
+}
+
+func TestPKIXNameString(t *testing.T) {
+	der, err := base64.StdEncoding.DecodeString(certBytes)
+	if err != nil {
+		t.Fatal(err)
+	}
+	certs, err := ParseCertificates(der)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Check that parsed non-standard attributes are printed.
+	rdns := pkix.Name{
+		Locality: []string{"Gophertown"},
+		ExtraNames: []pkix.AttributeTypeAndValue{
+			{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 5}), Value: "golang.org"}},
+	}.ToRDNSequence()
+	nn := pkix.Name{}
+	nn.FillFromRDNSequence(&rdns)
+
+	// Check that zero-length non-nil ExtraNames hide Names.
+	extra := []pkix.AttributeTypeAndValue{
+		{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 5}), Value: "backing array"}}
+	extraNotNil := pkix.Name{
+		Locality:   []string{"Gophertown"},
+		ExtraNames: extra[:0],
+		Names: []pkix.AttributeTypeAndValue{
+			{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 5}), Value: "golang.org"}},
+	}
+
+	tests := []struct {
+		dn   pkix.Name
+		want string
+	}{
+		{nn, "L=Gophertown,1.2.3.4.5=#130a676f6c616e672e6f7267"},
+		{extraNotNil, "L=Gophertown"},
+		{pkix.Name{
+			CommonName:         "Steve Kille",
+			Organization:       []string{"Isode Limited"},
+			OrganizationalUnit: []string{"RFCs"},
+			Locality:           []string{"Richmond"},
+			Province:           []string{"Surrey"},
+			StreetAddress:      []string{"The Square"},
+			PostalCode:         []string{"TW9 1DT"},
+			SerialNumber:       "RFC 2253",
+			Country:            []string{"GB"},
+		}, "SERIALNUMBER=RFC 2253,CN=Steve Kille,OU=RFCs,O=Isode Limited,POSTALCODE=TW9 1DT,STREET=The Square,L=Richmond,ST=Surrey,C=GB"},
+		{certs[0].Subject,
+			"CN=mail.google.com,O=Google LLC,L=Mountain View,ST=California,C=US"},
+		{pkix.Name{
+			Organization: []string{"#Google, Inc. \n-> 'Alphabet\" "},
+			Country:      []string{"US"},
+		}, "O=\\#Google\\, Inc. \n-\\> 'Alphabet\\\"\\ ,C=US"},
+		{pkix.Name{
+			CommonName:   "foo.com",
+			Organization: []string{"Gopher Industries"},
+			ExtraNames: []pkix.AttributeTypeAndValue{
+				{Type: asn1.ObjectIdentifier([]int{2, 5, 4, 3}), Value: "bar.com"}},
+		}, "CN=bar.com,O=Gopher Industries"},
+		{pkix.Name{
+			Locality: []string{"Gophertown"},
+			ExtraNames: []pkix.AttributeTypeAndValue{
+				{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 5}), Value: "golang.org"}},
+		}, "1.2.3.4.5=#130a676f6c616e672e6f7267,L=Gophertown"},
+		// If there are no ExtraNames, the Names are printed instead.
+		{pkix.Name{
+			Locality: []string{"Gophertown"},
+			Names: []pkix.AttributeTypeAndValue{
+				{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 5}), Value: "golang.org"}},
+		}, "L=Gophertown,1.2.3.4.5=#130a676f6c616e672e6f7267"},
+		// If there are both, print only the ExtraNames.
+		{pkix.Name{
+			Locality: []string{"Gophertown"},
+			ExtraNames: []pkix.AttributeTypeAndValue{
+				{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 5}), Value: "golang.org"}},
+			Names: []pkix.AttributeTypeAndValue{
+				{Type: asn1.ObjectIdentifier([]int{1, 2, 3, 4, 6}), Value: "example.com"}},
+		}, "1.2.3.4.5=#130a676f6c616e672e6f7267,L=Gophertown"},
+	}
+
+	for i, test := range tests {
+		if got := test.dn.String(); got != test.want {
+			t.Errorf("#%d: String() = \n%s\n, want \n%s", i, got, test.want)
+		}
+	}
+
+	if extra[0].Value != "backing array" {
+		t.Errorf("the backing array of an empty ExtraNames got modified by String")
+	}
+}
+
+func TestRDNSequenceString(t *testing.T) {
+	// Test some extra cases that get lost in pkix.Name conversions such as
+	// multi-valued attributes.
+
+	var (
+		oidCountry            = []int{2, 5, 4, 6}
+		oidOrganization       = []int{2, 5, 4, 10}
+		oidOrganizationalUnit = []int{2, 5, 4, 11}
+		oidCommonName         = []int{2, 5, 4, 3}
+	)
+
+	tests := []struct {
+		seq  pkix.RDNSequence
+		want string
+	}{
+		{
+			seq: pkix.RDNSequence{
+				pkix.RelativeDistinguishedNameSET{
+					pkix.AttributeTypeAndValue{Type: oidCountry, Value: "US"},
+				},
+				pkix.RelativeDistinguishedNameSET{
+					pkix.AttributeTypeAndValue{Type: oidOrganization, Value: "Widget Inc."},
+				},
+				pkix.RelativeDistinguishedNameSET{
+					pkix.AttributeTypeAndValue{Type: oidOrganizationalUnit, Value: "Sales"},
+					pkix.AttributeTypeAndValue{Type: oidCommonName, Value: "J. Smith"},
+				},
+			},
+			want: "OU=Sales+CN=J. Smith,O=Widget Inc.,C=US",
+		},
+	}
+
+	for i, test := range tests {
+		if got := test.seq.String(); got != test.want {
+			t.Errorf("#%d: String() = \n%s\n, want \n%s", i, got, test.want)
+		}
+	}
+}
+
+const criticalNameConstraintWithUnknownTypePEM = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestCriticalNameConstraintWithUnknownType(t *testing.T) {
+	block, _ := pem.Decode([]byte(criticalNameConstraintWithUnknownTypePEM))
+	cert, err := ParseCertificate(block.Bytes)
+	if err != nil {
+		t.Fatalf("unexpected parsing failure: %s", err)
+	}
+
+	if l := len(cert.UnhandledCriticalExtensions); l != 1 {
+		t.Fatalf("expected one unhandled critical extension, but found %d", l)
+	}
+}
+
+const badIPMaskPEM = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestBadIPMask(t *testing.T) {
+	block, _ := pem.Decode([]byte(badIPMaskPEM))
+	_, err := ParseCertificate(block.Bytes)
+	if err == nil {
+		t.Fatalf("unexpected success")
+	}
+
+	const expected = "contained invalid mask"
+	if !strings.Contains(err.Error(), expected) {
+		t.Fatalf("expected %q in error but got: %s", expected, err)
+	}
+}
+
+const additionalGeneralSubtreePEM = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestAdditionFieldsInGeneralSubtree(t *testing.T) {
+	// Very rarely, certificates can include additional fields in the
+	// GeneralSubtree structure. This tests that such certificates can be
+	// parsed.
+	block, _ := pem.Decode([]byte(additionalGeneralSubtreePEM))
+	if _, err := ParseCertificate(block.Bytes); err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+}
+
+func TestEmptySubject(t *testing.T) {
+	template := Certificate{
+		SerialNumber: big.NewInt(1),
+		DNSNames:     []string{"example.com"},
+	}
+
+	derBytes, err := CreateCertificate(rand.Reader, &template, &template, &testPrivateKey.PublicKey, testPrivateKey)
+	if err != nil {
+		t.Fatalf("failed to create certificate: %s", err)
+	}
+
+	cert, err := ParseCertificate(derBytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+
+	for _, ext := range cert.Extensions {
+		if ext.Id.Equal(oidExtensionSubjectAltName) {
+			if !ext.Critical {
+				t.Fatal("SAN extension is not critical")
+			}
+			return
+		}
+	}
+
+	t.Fatal("SAN extension is missing")
+}
+
+// multipleURLsInCRLDPPEM contains two URLs in a single CRL DistributionPoint
+// structure. It is taken from https://crt.sh/?id=12721534.
+const multipleURLsInCRLDPPEM = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+
+func TestMultipleURLsInCRLDP(t *testing.T) {
+	block, _ := pem.Decode([]byte(multipleURLsInCRLDPPEM))
+	cert, err := ParseCertificate(block.Bytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+
+	want := []string{
+		"http://epscd.catcert.net/crl/ec-acc.crl",
+		"http://epscd2.catcert.net/crl/ec-acc.crl",
+	}
+	if got := cert.CRLDistributionPoints; !reflect.DeepEqual(got, want) {
+		t.Errorf("CRL distribution points = %#v, want #%v", got, want)
+	}
+}
+
+const hexPKCS1TestPKCS8Key = "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"
+const hexPKCS1TestECKey = "3081a40201010430bdb9839c08ee793d1157886a7a758a3c8b2a17a4df48f17ace57c72c56b4723cf21dcda21d4e1ad57ff034f19fcfd98ea00706052b81040022a16403620004feea808b5ee2429cfcce13c32160e1c960990bd050bb0fdf7222f3decd0a55008e32a6aa3c9062051c4cba92a7a3b178b24567412d43cdd2f882fa5addddd726fe3e208d2c26d733a773a597abb749714df7256ead5105fa6e7b3650de236b50"
+
+var pkcs1MismatchKeyTests = []struct {
+	hexKey        string
+	errorContains string
+}{
+	{hexKey: hexPKCS1TestPKCS8Key, errorContains: "use ParsePKCS8PrivateKey instead"},
+	{hexKey: hexPKCS1TestECKey, errorContains: "use ParseECPrivateKey instead"},
+}
+
+func TestPKCS1MismatchKeyFormat(t *testing.T) {
+	for i, test := range pkcs1MismatchKeyTests {
+		derBytes, _ := hex.DecodeString(test.hexKey)
+		_, err := ParsePKCS1PrivateKey(derBytes)
+		if !strings.Contains(err.Error(), test.errorContains) {
+			t.Errorf("#%d: expected error containing %q, got %s", i, test.errorContains, err)
+		}
+	}
+}
+
+func TestCreateRevocationList(t *testing.T) {
+	ec256Priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatalf("Failed to generate ECDSA P256 key: %s", err)
+	}
+	_, ed25519Priv, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		t.Fatalf("Failed to generate Ed25519 key: %s", err)
+	}
+
+	// Generation command:
+	// openssl req -x509 -newkey rsa -keyout key.pem -out cert.pem -days 365 -nodes -subj '/C=US/ST=California/L=San Francisco/O=Internet Widgets, Inc./OU=WWW/CN=Root/emailAddress=admin@example.com' -sha256 -addext basicConstraints=CA:TRUE -addext "keyUsage = digitalSignature, keyEncipherment, dataEncipherment, cRLSign, keyCertSign" -utf8
+	utf8CAStr := "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"
+	utf8CABytes, _ := base64.StdEncoding.DecodeString(utf8CAStr)
+	utf8CA, _ := ParseCertificate(utf8CABytes)
+
+	utf8KeyStr := "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"
+	utf8KeyBytes, _ := base64.StdEncoding.DecodeString(utf8KeyStr)
+	utf8KeyRaw, _ := ParsePKCS8PrivateKey(utf8KeyBytes)
+	utf8Key := utf8KeyRaw.(crypto.Signer)
+
+	tests := []struct {
+		name          string
+		key           crypto.Signer
+		issuer        *Certificate
+		template      *RevocationList
+		expectedError string
+	}{
+		{
+			name:          "nil template",
+			key:           ec256Priv,
+			issuer:        nil,
+			template:      nil,
+			expectedError: "x509: template can not be nil",
+		},
+		{
+			name:          "nil issuer",
+			key:           ec256Priv,
+			issuer:        nil,
+			template:      &RevocationList{},
+			expectedError: "x509: issuer can not be nil",
+		},
+		{
+			name: "issuer doesn't have crlSign key usage bit set",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCertSign,
+			},
+			template:      &RevocationList{},
+			expectedError: "x509: issuer must have the crlSign key usage bit set",
+		},
+		{
+			name: "issuer missing SubjectKeyId",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+			},
+			template:      &RevocationList{},
+			expectedError: "x509: issuer certificate doesn't contain a subject key identifier",
+		},
+		{
+			name: "nextUpdate before thisUpdate",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				ThisUpdate: time.Time{}.Add(time.Hour),
+				NextUpdate: time.Time{},
+			},
+			expectedError: "x509: template.ThisUpdate is after template.NextUpdate",
+		},
+		{
+			name: "nil Number",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+			expectedError: "x509: template contains nil Number field",
+		},
+		{
+			name: "long Number",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+				Number:     big.NewInt(0).SetBytes(append([]byte{1}, make([]byte, 20)...)),
+			},
+			expectedError: "x509: CRL number exceeds 20 octets",
+		},
+		{
+			name: "long Number (20 bytes, MSB set)",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+				Number:     big.NewInt(0).SetBytes(append([]byte{255}, make([]byte, 19)...)),
+			},
+			expectedError: "x509: CRL number exceeds 20 octets",
+		},
+		{
+			name: "invalid signature algorithm",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				SignatureAlgorithm: SHA256WithRSA,
+				RevokedCertificates: []pkix.RevokedCertificate{
+					{
+						SerialNumber:   big.NewInt(2),
+						RevocationTime: time.Time{}.Add(time.Hour),
+					},
+				},
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+			expectedError: "x509: requested SignatureAlgorithm does not match private key type",
+		},
+		{
+			name: "valid",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				RevokedCertificates: []pkix.RevokedCertificate{
+					{
+						SerialNumber:   big.NewInt(2),
+						RevocationTime: time.Time{}.Add(time.Hour),
+					},
+				},
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+		},
+		{
+			name: "valid, extra entry extension",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				RevokedCertificates: []pkix.RevokedCertificate{
+					{
+						SerialNumber:   big.NewInt(2),
+						RevocationTime: time.Time{}.Add(time.Hour),
+						Extensions: []pkix.Extension{
+							{
+								Id:    []int{2, 5, 29, 99},
+								Value: []byte{5, 0},
+							},
+						},
+					},
+				},
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+		},
+		{
+			name: "valid, Ed25519 key",
+			key:  ed25519Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				RevokedCertificates: []pkix.RevokedCertificate{
+					{
+						SerialNumber:   big.NewInt(2),
+						RevocationTime: time.Time{}.Add(time.Hour),
+					},
+				},
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+		},
+		{
+			name: "valid, non-default signature algorithm",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				SignatureAlgorithm: ECDSAWithSHA512,
+				RevokedCertificates: []pkix.RevokedCertificate{
+					{
+						SerialNumber:   big.NewInt(2),
+						RevocationTime: time.Time{}.Add(time.Hour),
+					},
+				},
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+		},
+		{
+			name: "valid, extra extension",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				RevokedCertificates: []pkix.RevokedCertificate{
+					{
+						SerialNumber:   big.NewInt(2),
+						RevocationTime: time.Time{}.Add(time.Hour),
+					},
+				},
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+				ExtraExtensions: []pkix.Extension{
+					{
+						Id:    []int{2, 5, 29, 99},
+						Value: []byte{5, 0},
+					},
+				},
+			},
+		},
+		{
+			name: "valid, empty list",
+			key:  ec256Priv,
+			issuer: &Certificate{
+				KeyUsage: KeyUsageCRLSign,
+				Subject: pkix.Name{
+					CommonName: "testing",
+				},
+				SubjectKeyId: []byte{1, 2, 3},
+			},
+			template: &RevocationList{
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+		},
+		{
+			name:   "valid CA with utf8 Subject fields including Email, empty list",
+			key:    utf8Key,
+			issuer: utf8CA,
+			template: &RevocationList{
+				Number:     big.NewInt(5),
+				ThisUpdate: time.Time{}.Add(time.Hour * 24),
+				NextUpdate: time.Time{}.Add(time.Hour * 48),
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			crl, err := CreateRevocationList(rand.Reader, tc.template, tc.issuer, tc.key)
+			if err != nil && tc.expectedError == "" {
+				t.Fatalf("CreateRevocationList failed unexpectedly: %s", err)
+			} else if err != nil && tc.expectedError != err.Error() {
+				t.Fatalf("CreateRevocationList failed unexpectedly, wanted: %s, got: %s", tc.expectedError, err)
+			} else if err == nil && tc.expectedError != "" {
+				t.Fatalf("CreateRevocationList didn't fail, expected: %s", tc.expectedError)
+			}
+			if tc.expectedError != "" {
+				return
+			}
+
+			parsedCRL, err := ParseRevocationList(crl)
+			if err != nil {
+				t.Fatalf("Failed to parse generated CRL: %s", err)
+			}
+
+			if tc.template.SignatureAlgorithm != UnknownSignatureAlgorithm &&
+				parsedCRL.SignatureAlgorithm != tc.template.SignatureAlgorithm {
+				t.Fatalf("SignatureAlgorithm mismatch: got %v; want %v.", parsedCRL.SignatureAlgorithm,
+					tc.template.SignatureAlgorithm)
+			}
+
+			if !reflect.DeepEqual(parsedCRL.RevokedCertificates, tc.template.RevokedCertificates) {
+				t.Fatalf("RevokedCertificates mismatch: got %v; want %v.",
+					parsedCRL.RevokedCertificates, tc.template.RevokedCertificates)
+			}
+
+			if len(parsedCRL.Extensions) != 2+len(tc.template.ExtraExtensions) {
+				t.Fatalf("Generated CRL has wrong number of extensions, wanted: %d, got: %d", 2+len(tc.template.ExtraExtensions), len(parsedCRL.Extensions))
+			}
+			expectedAKI, err := asn1.Marshal(authKeyId{Id: tc.issuer.SubjectKeyId})
+			if err != nil {
+				t.Fatalf("asn1.Marshal failed: %s", err)
+			}
+			akiExt := pkix.Extension{
+				Id:    oidExtensionAuthorityKeyId,
+				Value: expectedAKI,
+			}
+			if !reflect.DeepEqual(parsedCRL.Extensions[0], akiExt) {
+				t.Fatalf("Unexpected first extension: got %v, want %v",
+					parsedCRL.Extensions[0], akiExt)
+			}
+			expectedNum, err := asn1.Marshal(tc.template.Number)
+			if err != nil {
+				t.Fatalf("asn1.Marshal failed: %s", err)
+			}
+			crlExt := pkix.Extension{
+				Id:    oidExtensionCRLNumber,
+				Value: expectedNum,
+			}
+			if !reflect.DeepEqual(parsedCRL.Extensions[1], crlExt) {
+				t.Fatalf("Unexpected second extension: got %v, want %v",
+					parsedCRL.Extensions[1], crlExt)
+			}
+
+			// With Go 1.19's updated RevocationList, we can now directly compare
+			// the RawSubject of the certificate to RawIssuer on the parsed CRL.
+			// However, this doesn't work with our hacked issuers above (that
+			// aren't parsed from a proper DER bundle but are instead manually
+			// constructed). Prefer RawSubject when it is set.
+			if len(tc.issuer.RawSubject) > 0 {
+				issuerSubj, err := subjectBytes(tc.issuer)
+				if err != nil {
+					t.Fatalf("failed to get issuer subject: %s", err)
+				}
+				if !bytes.Equal(issuerSubj, parsedCRL.RawIssuer) {
+					t.Fatalf("Unexpected issuer subject; wanted: %v, got: %v", hex.EncodeToString(issuerSubj), hex.EncodeToString(parsedCRL.RawIssuer))
+				}
+			} else {
+				// When we hack our custom Subject in the test cases above,
+				// we don't set the additional fields (such as Names) in the
+				// hacked issuer. Round-trip a parsing of pkix.Name so that
+				// we add these missing fields for the comparison.
+				issuerRDN := tc.issuer.Subject.ToRDNSequence()
+				var caIssuer pkix.Name
+				caIssuer.FillFromRDNSequence(&issuerRDN)
+				if !reflect.DeepEqual(caIssuer, parsedCRL.Issuer) {
+					t.Fatalf("Expected issuer.Subject, parsedCRL.Issuer to be the same; wanted: %#v, got: %#v", caIssuer, parsedCRL.Issuer)
+				}
+			}
+
+			if len(parsedCRL.Extensions[2:]) == 0 && len(tc.template.ExtraExtensions) == 0 {
+				// If we don't have anything to check return early so we don't
+				// hit a [] != nil false positive below.
+				return
+			}
+			if !reflect.DeepEqual(parsedCRL.Extensions[2:], tc.template.ExtraExtensions) {
+				t.Fatalf("Extensions mismatch: got %v; want %v.",
+					parsedCRL.Extensions[2:], tc.template.ExtraExtensions)
+			}
+
+			if tc.template.Number != nil && parsedCRL.Number == nil {
+				t.Fatalf("Generated CRL missing Number: got nil, want %s",
+					tc.template.Number.String())
+			}
+			if tc.template.Number != nil && tc.template.Number.Cmp(parsedCRL.Number) != 0 {
+				t.Fatalf("Generated CRL has wrong Number: got %s, want %s",
+					parsedCRL.Number.String(), tc.template.Number.String())
+			}
+			if !bytes.Equal(parsedCRL.AuthorityKeyId, expectedAKI) {
+				t.Fatalf("Generated CRL has wrong Number: got %x, want %x",
+					parsedCRL.AuthorityKeyId, expectedAKI)
+			}
+		})
+	}
+}
+
+func TestRSAPSAParameters(t *testing.T) {
+	generateParams := func(hashFunc crypto.Hash) []byte {
+		var hashOID asn1.ObjectIdentifier
+
+		switch hashFunc {
+		case crypto.SHA256:
+			hashOID = oidSHA256
+		case crypto.SHA384:
+			hashOID = oidSHA384
+		case crypto.SHA512:
+			hashOID = oidSHA512
+		}
+
+		params := pssParameters{
+			Hash: pkix.AlgorithmIdentifier{
+				Algorithm:  hashOID,
+				Parameters: asn1.NullRawValue,
+			},
+			MGF: pkix.AlgorithmIdentifier{
+				Algorithm: oidMGF1,
+			},
+			SaltLength:   hashFunc.Size(),
+			TrailerField: 1,
+		}
+
+		mgf1Params := pkix.AlgorithmIdentifier{
+			Algorithm:  hashOID,
+			Parameters: asn1.NullRawValue,
+		}
+
+		var err error
+		params.MGF.Parameters.FullBytes, err = asn1.Marshal(mgf1Params)
+		if err != nil {
+			t.Fatalf("failed to marshal MGF parameters: %s", err)
+		}
+
+		serialized, err := asn1.Marshal(params)
+		if err != nil {
+			t.Fatalf("failed to marshal parameters: %s", err)
+		}
+
+		return serialized
+	}
+
+	for h, params := range hashToPSSParameters {
+		generated := generateParams(h)
+		if !bytes.Equal(params.FullBytes, generated) {
+			t.Errorf("hardcoded parameters for %s didn't match generated parameters: got (generated) %x, wanted (hardcoded) %x", h, generated, params.FullBytes)
+		}
+	}
+}
+
+func TestUnknownExtKey(t *testing.T) {
+	const errorContains = "unknown extended key usage"
+
+	template := &Certificate{
+		SerialNumber: big.NewInt(10),
+		DNSNames:     []string{"foo"},
+		ExtKeyUsage:  []ExtKeyUsage{ExtKeyUsage(-1)},
+	}
+	signer, err := rsa.GenerateKey(rand.Reader, 1024)
+	if err != nil {
+		t.Errorf("failed to generate key for TestUnknownExtKey")
+	}
+
+	_, err = CreateCertificate(rand.Reader, template, template, signer.Public(), signer)
+	if !strings.Contains(err.Error(), errorContains) {
+		t.Errorf("expected error containing %q, got %s", errorContains, err)
+	}
+}
+
+func TestIA5SANEnforcement(t *testing.T) {
+	k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatalf("ecdsa.GenerateKey failed: %s", err)
+	}
+
+	testURL, err := url.Parse("https://example.com/")
+	if err != nil {
+		t.Fatalf("url.Parse failed: %s", err)
+	}
+	testURL.RawQuery = "∞"
+
+	marshalTests := []struct {
+		name          string
+		template      *Certificate
+		expectedError string
+	}{
+		{
+			name: "marshal: unicode dNSName",
+			template: &Certificate{
+				SerialNumber: big.NewInt(0),
+				DNSNames:     []string{"∞"},
+			},
+			expectedError: "x509: \"∞\" cannot be encoded as an IA5String",
+		},
+		{
+			name: "marshal: unicode rfc822Name",
+			template: &Certificate{
+				SerialNumber:   big.NewInt(0),
+				EmailAddresses: []string{"∞"},
+			},
+			expectedError: "x509: \"∞\" cannot be encoded as an IA5String",
+		},
+		{
+			name: "marshal: unicode uniformResourceIdentifier",
+			template: &Certificate{
+				SerialNumber: big.NewInt(0),
+				URIs:         []*url.URL{testURL},
+			},
+			expectedError: "x509: \"https://example.com/?∞\" cannot be encoded as an IA5String",
+		},
+	}
+
+	for _, tc := range marshalTests {
+		t.Run(tc.name, func(t *testing.T) {
+			_, err := CreateCertificate(rand.Reader, tc.template, tc.template, k.Public(), k)
+			if err == nil {
+				t.Errorf("expected CreateCertificate to fail with template: %v", tc.template)
+			} else if err.Error() != tc.expectedError {
+				t.Errorf("unexpected error: got %q, want %q", err.Error(), tc.expectedError)
+			}
+		})
+	}
+
+	unmarshalTests := []struct {
+		name          string
+		cert          string
+		expectedError string
+	}{
+		{
+			name:          "unmarshal: unicode dNSName",
+			cert:          "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",
+			expectedError: "x509: SAN dNSName is malformed",
+		},
+		{
+			name:          "unmarshal: unicode rfc822Name",
+			cert:          "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",
+			expectedError: "x509: SAN rfc822Name is malformed",
+		},
+		{
+			name:          "unmarshal: unicode uniformResourceIdentifier",
+			cert:          "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",
+			expectedError: "x509: SAN uniformResourceIdentifier is malformed",
+		},
+	}
+
+	for _, tc := range unmarshalTests {
+		der, err := hex.DecodeString(tc.cert)
+		if err != nil {
+			t.Fatalf("failed to decode test cert: %s", err)
+		}
+		_, err = ParseCertificate(der)
+		if err == nil {
+			t.Error("expected CreateCertificate to fail")
+		} else if err.Error() != tc.expectedError {
+			t.Errorf("unexpected error: got %q, want %q", err.Error(), tc.expectedError)
+		}
+	}
+}
+
+func BenchmarkCreateCertificate(b *testing.B) {
+	template := &Certificate{
+		SerialNumber: big.NewInt(10),
+		DNSNames:     []string{"example.com"},
+	}
+	tests := []struct {
+		name string
+		gen  func() crypto.Signer
+	}{
+		{
+			name: "RSA 2048",
+			gen: func() crypto.Signer {
+				k, err := rsa.GenerateKey(rand.Reader, 2048)
+				if err != nil {
+					b.Fatalf("failed to generate test key: %s", err)
+				}
+				return k
+			},
+		},
+		{
+			name: "ECDSA P256",
+			gen: func() crypto.Signer {
+				k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+				if err != nil {
+					b.Fatalf("failed to generate test key: %s", err)
+				}
+				return k
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		k := tc.gen()
+		b.ResetTimer()
+		b.Run(tc.name, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				_, err := CreateCertificate(rand.Reader, template, template, k.Public(), k)
+				if err != nil {
+					b.Fatalf("failed to create certificate: %s", err)
+				}
+			}
+		})
+	}
+}
+
+type brokenSigner struct {
+	pub crypto.PublicKey
+}
+
+func (bs *brokenSigner) Public() crypto.PublicKey {
+	return bs.pub
+}
+
+func (bs *brokenSigner) Sign(_ io.Reader, _ []byte, _ crypto.SignerOpts) ([]byte, error) {
+	return []byte{1, 2, 3}, nil
+}
+
+func TestCreateCertificateBrokenSigner(t *testing.T) {
+	template := &Certificate{
+		SerialNumber: big.NewInt(10),
+		DNSNames:     []string{"example.com"},
+	}
+	k, err := rsa.GenerateKey(rand.Reader, 1024)
+	if err != nil {
+		t.Fatalf("failed to generate test key: %s", err)
+	}
+	expectedErr := "x509: signature over certificate returned by signer is invalid: crypto/rsa: verification error"
+	_, err = CreateCertificate(rand.Reader, template, template, k.Public(), &brokenSigner{k.Public()})
+	if err == nil {
+		t.Fatal("expected CreateCertificate to fail with a broken signer")
+	} else if err.Error() != expectedErr {
+		t.Fatalf("CreateCertificate returned an unexpected error: got %q, want %q", err, expectedErr)
+	}
+}
+
+func TestCreateCertificateLegacy(t *testing.T) {
+	sigAlg := MD5WithRSA
+	template := &Certificate{
+		SerialNumber:       big.NewInt(10),
+		DNSNames:           []string{"example.com"},
+		SignatureAlgorithm: sigAlg,
+	}
+	_, err := CreateCertificate(rand.Reader, template, template, testPrivateKey.Public(), &brokenSigner{testPrivateKey.Public()})
+	if err == nil {
+		t.Fatal("CreateCertificate didn't fail when SignatureAlgorithm = MD5WithRSA")
+	}
+}
+
+func (s *CertPool) mustCert(t *testing.T, n int) *Certificate {
+	c, err := s.lazyCerts[n].getCert()
+	if err != nil {
+		t.Fatalf("failed to load cert %d: %v", n, err)
+	}
+	return c
+}
+
+func allCerts(t *testing.T, p *CertPool) []*Certificate {
+	all := make([]*Certificate, p.len())
+	for i := range all {
+		all[i] = p.mustCert(t, i)
+	}
+	return all
+}
+
+// certPoolEqual reports whether a and b are equal, except for the
+// function pointers.
+func certPoolEqual(a, b *CertPool) bool {
+	if (a != nil) != (b != nil) {
+		return false
+	}
+	if a == nil {
+		return true
+	}
+	if !reflect.DeepEqual(a.byName, b.byName) ||
+		len(a.lazyCerts) != len(b.lazyCerts) {
+		return false
+	}
+	for i := range a.lazyCerts {
+		la, lb := a.lazyCerts[i], b.lazyCerts[i]
+		if !bytes.Equal(la.rawSubject, lb.rawSubject) {
+			return false
+		}
+		ca, err := la.getCert()
+		if err != nil {
+			panic(err)
+		}
+		cb, err := la.getCert()
+		if err != nil {
+			panic(err)
+		}
+		if !ca.Equal(cb) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func TestCertificateRequestRoundtripFields(t *testing.T) {
+	urlA, err := url.Parse("https://example.com/_")
+	if err != nil {
+		t.Fatal(err)
+	}
+	urlB, err := url.Parse("https://example.org/_")
+	if err != nil {
+		t.Fatal(err)
+	}
+	in := &CertificateRequest{
+		DNSNames:       []string{"example.com", "example.org"},
+		EmailAddresses: []string{"a@example.com", "b@example.com"},
+		IPAddresses:    []net.IP{net.IPv4(192, 0, 2, 0), net.IPv6loopback},
+		URIs:           []*url.URL{urlA, urlB},
+	}
+	out := marshalAndParseCSR(t, in)
+
+	if !reflect.DeepEqual(in.DNSNames, out.DNSNames) {
+		t.Fatalf("Unexpected DNSNames: got %v, want %v", out.DNSNames, in.DNSNames)
+	}
+	if !reflect.DeepEqual(in.EmailAddresses, out.EmailAddresses) {
+		t.Fatalf("Unexpected EmailAddresses: got %v, want %v", out.EmailAddresses, in.EmailAddresses)
+	}
+	if len(in.IPAddresses) != len(out.IPAddresses) ||
+		!in.IPAddresses[0].Equal(out.IPAddresses[0]) ||
+		!in.IPAddresses[1].Equal(out.IPAddresses[1]) {
+		t.Fatalf("Unexpected IPAddresses: got %v, want %v", out.IPAddresses, in.IPAddresses)
+	}
+	if !reflect.DeepEqual(in.URIs, out.URIs) {
+		t.Fatalf("Unexpected URIs: got %v, want %v", out.URIs, in.URIs)
+	}
+}
+
+func BenchmarkParseCertificate(b *testing.B) {
+	cases := []struct {
+		name string
+		pem  string
+	}{
+		{
+			name: "ecdsa leaf",
+			pem: `-----BEGIN CERTIFICATE-----
+MIIINjCCBx6gAwIBAgIQHdQ6oBMoe/MJAAAAAEHzmTANBgkqhkiG9w0BAQsFADBG
+MQswCQYDVQQGEwJVUzEiMCAGA1UEChMZR29vZ2xlIFRydXN0IFNlcnZpY2VzIExM
+QzETMBEGA1UEAxMKR1RTIENBIDFDMzAeFw0yMDEyMDgwOTExMzZaFw0yMTAzMDIw
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+svXC3HUd3apM2Yy3xJAlk/mUkzVXfdJZ+Zy1huNsUoJ+gM8rmpyGhYyx
+-----END CERTIFICATE-----`,
+		},
+		{
+			name: "rsa leaf",
+			pem: `-----BEGIN CERTIFICATE-----
+MIIJXjCCCEagAwIBAgIRAPYaTUsjP4iRBQAAAACHSSgwDQYJKoZIhvcNAQELBQAw
+QjELMAkGA1UEBhMCVVMxHjAcBgNVBAoTFUdvb2dsZSBUcnVzdCBTZXJ2aWNlczET
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+cHBzLmNughJnb29nbGVjb21tZXJjZS5jb22CGHNvdXJjZS5hbmRyb2lkLmdvb2ds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+-----END CERTIFICATE-----`,
+		},
+	}
+	for _, c := range cases {
+		b.Run(c.name, func(b *testing.B) {
+			pemBlock, _ := pem.Decode([]byte(c.pem))
+			b.ReportAllocs()
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				_, err := ParseCertificate(pemBlock.Bytes)
+				if err != nil {
+					b.Fatal(err)
+				}
+			}
+		})
+	}
+}
+
+func TestParseCertificateRawEquals(t *testing.T) {
+	p, _ := pem.Decode([]byte(pemCertificate))
+	cert, err := ParseCertificate(p.Bytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+	if !bytes.Equal(p.Bytes, cert.Raw) {
+		t.Fatalf("unexpected Certificate.Raw\ngot: %x\nwant: %x\n", cert.Raw, p.Bytes)
+	}
+}
+
+// mismatchingSigAlgIDPEM contains a certificate where the Certificate
+// signatureAlgorithm and the TBSCertificate signature contain
+// mismatching OIDs
+const mismatchingSigAlgIDPEM = `-----BEGIN CERTIFICATE-----
+MIIBBzCBrqADAgECAgEAMAoGCCqGSM49BAMCMAAwIhgPMDAwMTAxMDEwMDAwMDBa
+GA8wMDAxMDEwMTAwMDAwMFowADBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABOqV
+EDuVXxwZgIU3+dOwv1SsMu0xuV48hf7xmK8n7sAMYgllB+96DnPqBeboJj4snYnx
+0AcE0PDVQ1l4Z3YXsQWjFTATMBEGA1UdEQEB/wQHMAWCA2FzZDAKBggqhkjOPQQD
+AwNIADBFAiBi1jz/T2HT5nAfrD7zsgR+68qh7Erc6Q4qlxYBOgKG4QIhAOtjIn+Q
+tA+bq+55P3ntxTOVRq0nv1mwnkjwt9cQR9Fn
+-----END CERTIFICATE-----`
+
+// mismatchingSigAlgParamPEM contains a certificate where the Certificate
+// signatureAlgorithm and the TBSCertificate signature contain
+// mismatching parameters
+const mismatchingSigAlgParamPEM = `-----BEGIN CERTIFICATE-----
+MIIBCTCBrqADAgECAgEAMAoGCCqGSM49BAMCMAAwIhgPMDAwMTAxMDEwMDAwMDBa
+GA8wMDAxMDEwMTAwMDAwMFowADBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABOqV
+EDuVXxwZgIU3+dOwv1SsMu0xuV48hf7xmK8n7sAMYgllB+96DnPqBeboJj4snYnx
+0AcE0PDVQ1l4Z3YXsQWjFTATMBEGA1UdEQEB/wQHMAWCA2FzZDAMBggqhkjOPQQD
+AgUAA0gAMEUCIGLWPP9PYdPmcB+sPvOyBH7ryqHsStzpDiqXFgE6AobhAiEA62Mi
+f5C0D5ur7nk/ee3FM5VGrSe/WbCeSPC31xBH0Wc=
+-----END CERTIFICATE-----`
+
+func TestSigAlgMismatch(t *testing.T) {
+	for _, certPEM := range []string{mismatchingSigAlgIDPEM, mismatchingSigAlgParamPEM} {
+		b, _ := pem.Decode([]byte(certPEM))
+		if b == nil {
+			t.Fatalf("couldn't decode test certificate")
+		}
+		_, err := ParseCertificate(b.Bytes)
+		if err == nil {
+			t.Fatalf("expected ParseCertificate to fail")
+		}
+		expected := "x509: inner and outer signature algorithm identifiers don't match"
+		if err.Error() != expected {
+			t.Errorf("unexpected error from ParseCertificate: got %q, want %q", err.Error(), expected)
+		}
+	}
+}
+
+const optionalAuthKeyIDPEM = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestAuthKeyIdOptional(t *testing.T) {
+	b, _ := pem.Decode([]byte(optionalAuthKeyIDPEM))
+	if b == nil {
+		t.Fatalf("couldn't decode test certificate")
+	}
+	_, err := ParseCertificate(b.Bytes)
+	if err != nil {
+		t.Fatalf("ParseCertificate to failed to parse certificate with optional authority key identifier fields: %s", err)
+	}
+}
+
+const largeOIDPEM = `
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number:
+            da:ba:53:19:1b:09:4b:82:b2:89:26:7d:c7:6f:a0:02
+        Signature Algorithm: sha256WithRSAEncryption
+        Issuer: O = Acme Co
+        Validity
+            Not Before: Dec 21 16:59:27 2021 GMT
+            Not After : Dec 21 16:59:27 2022 GMT
+        Subject: O = Acme Co
+        Subject Public Key Info:
+            Public Key Algorithm: rsaEncryption
+                RSA Public-Key: (2048 bit)
+                Modulus:
+                    00:bf:17:16:d8:bc:29:9c:16:e5:76:b4:93:15:78:
+                    ad:6e:45:c5:4a:63:46:a1:b2:76:71:65:51:9c:14:
+                    c4:ea:74:13:e4:34:df:2f:2c:65:11:e8:56:52:69:
+                    11:f9:0e:fc:77:bb:63:a8:7c:1a:c6:a1:7b:6e:6c:
+                    e7:18:25:25:c9:e8:fb:06:7f:a2:a9:98:fe:2a:bc:
+                    8a:b3:75:b6:b8:7d:b6:c9:6b:29:08:32:22:10:cb:
+                    8d:d6:60:c8:83:ad:f5:58:91:d6:11:e8:55:56:fb:
+                    8f:a3:a2:9f:48:cb:79:e4:65:4a:8c:a6:52:64:9f:
+                    99:38:35:d4:d5:ac:6f:cf:a0:cb:42:8c:07:eb:21:
+                    17:31:3a:eb:91:7b:62:43:a4:75:5f:ef:a7:2f:94:
+                    f8:69:0b:d4:ec:09:e6:00:c0:8c:dd:07:63:0b:e4:
+                    77:aa:60:18:3c:a0:e0:ae:0a:ea:0e:52:3b:b4:fa:
+                    6a:30:1b:50:62:21:73:53:33:01:60:a1:6b:99:58:
+                    00:f3:77:c6:0f:46:19:ca:c2:5d:cd:f5:e2:52:4d:
+                    84:94:23:d3:32:2f:ae:5f:da:43:a1:19:95:d2:17:
+                    dd:49:14:b4:d9:48:1c:08:13:93:8e:d5:09:43:21:
+                    b6:ce:52:e8:87:bb:d2:60:0d:c6:4e:bf:c5:93:6a:
+                    c6:bf
+                Exponent: 65537 (0x10001)
+        X509v3 extensions:
+            X509v3 Key Usage: critical
+                Digital Signature, Key Encipherment
+            X509v3 Extended Key Usage:
+                TLS Web Server Authentication
+            X509v3 Basic Constraints: critical
+                CA:FALSE
+            X509v3 Subject Alternative Name:
+                DNS:longOID.example
+            X509v3 Certificate Policies:
+                Policy: 1.3.6.1.4.1.311.21.8.1492336001
+
+    Signature Algorithm: sha256WithRSAEncryption
+         72:77:8b:de:48:fb:6d:9a:94:b1:be:d4:90:7d:4c:e6:d3:79:
+         fa:fb:fc:3e:d5:3d:e9:a0:ce:28:2b:2f:94:77:3f:87:f8:9c:
+         9f:91:1c:f3:f6:58:91:15:6b:24:b9:ca:ae:9f:ee:ca:c8:31:
+         db:1a:3d:bb:6b:83:6d:bc:81:8b:a1:79:d5:3e:bb:dd:93:fe:
+         35:3e:b7:99:e0:d6:eb:58:0c:fd:42:73:dc:49:da:e2:b7:ae:
+         15:ee:e6:cc:aa:ef:91:41:9a:18:46:8d:4a:39:65:a2:85:3c:
+         7f:0c:41:f8:0b:9c:e8:1f:35:36:60:8d:8c:e0:8e:18:b1:06:
+         57:d0:4e:c4:c3:cd:8f:6f:e7:76:02:52:da:03:43:61:2b:b3:
+         bf:19:fd:73:0d:6a:0b:b4:b6:cb:a9:6f:70:4e:53:2a:54:07:
+         b3:74:fd:85:49:57:5b:23:8d:8c:6b:53:2b:09:e8:41:a5:80:
+         3f:69:1b:11:d1:6b:13:35:2e:f9:d6:50:15:d9:91:38:42:43:
+         e9:17:af:67:d9:96:a4:d1:6a:4f:cc:b4:a7:8e:48:1f:00:72:
+         69:de:4d:f1:73:a4:47:12:67:e9:f9:07:3e:79:75:90:42:b8:
+         d4:b5:fd:d1:7e:35:04:f7:00:04:cf:f1:36:be:0f:27:81:1f:
+         a6:ba:88:6c
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestLargeOID(t *testing.T) {
+	// See Issue 49678.
+	b, _ := pem.Decode([]byte(largeOIDPEM))
+	if b == nil {
+		t.Fatalf("couldn't decode test certificate")
+	}
+	_, err := ParseCertificate(b.Bytes)
+	if err != nil {
+		t.Fatalf("ParseCertificate to failed to parse certificate with large OID: %s", err)
+	}
+}
+
+const uniqueIDPEM = `-----BEGIN CERTIFICATE-----
+MIIFsDCCBJigAwIBAgIIrOyC1ydafZMwDQYJKoZIhvcNAQEFBQAwgY4xgYswgYgG
+A1UEAx6BgABNAGkAYwByAG8AcwBvAGYAdAAgAEYAbwByAGUAZgByAG8AbgB0ACAA
+VABNAEcAIABIAFQAVABQAFMAIABJAG4AcwBwAGUAYwB0AGkAbwBuACAAQwBlAHIA
+dABpAGYAaQBjAGEAdABpAG8AbgAgAEEAdQB0AGgAbwByAGkAdAB5MB4XDTE0MDEx
+ODAwNDEwMFoXDTE1MTExNTA5Mzc1NlowgZYxCzAJBgNVBAYTAklEMRAwDgYDVQQI
+EwdqYWthcnRhMRIwEAYDVQQHEwlJbmRvbmVzaWExHDAaBgNVBAoTE3N0aG9ub3Jl
+aG90ZWxyZXNvcnQxHDAaBgNVBAsTE3N0aG9ub3JlaG90ZWxyZXNvcnQxJTAjBgNV
+BAMTHG1haWwuc3Rob25vcmVob3RlbHJlc29ydC5jb20wggEiMA0GCSqGSIb3DQEB
+AQUAA4IBDwAwggEKAoIBAQCvuu0qpI+Ko2X84Twkf84cRD/rgp6vpgc5Ebejx/D4
+PEVON5edZkazrMGocK/oQqIlRxx/lefponN/chlGcllcVVPWTuFjs8k+Aat6T1qp
+4iXxZekAqX+U4XZMIGJD3PckPL6G2RQSlF7/LhGCsRNRdKpMWSTbou2Ma39g52Kf
+gsl3SK/GwLiWpxpcSkNQD1hugguEIsQYLxbeNwpcheXZtxbBGguPzQ7rH8c5vuKU
+BkMOzaiNKLzHbBdFSrua8KWwCJg76Vdq/q36O9GlW6YgG3i+A4pCJjXWerI1lWwX
+Ktk5V+SvUHGey1bkDuZKJ6myMk2pGrrPWCT7jP7WskChAgMBAAGBCQBCr1dgEleo
+cKOCAfswggH3MIHDBgNVHREEgbswgbiCHG1haWwuc3Rob25vcmVob3RlbHJlc29y
+dC5jb22CIGFzaGNoc3ZyLnN0aG9ub3JlaG90ZWxyZXNvcnQuY29tgiRBdXRvRGlz
+Y292ZXIuc3Rob25vcmVob3RlbHJlc29ydC5jb22CHEF1dG9EaXNjb3Zlci5ob3Rl
+bHJlc29ydC5jb22CCEFTSENIU1ZSghdzdGhvbm9yZWhvdGVscmVzb3J0LmNvbYIP
+aG90ZWxyZXNvcnQuY29tMCEGCSsGAQQBgjcUAgQUHhIAVwBlAGIAUwBlAHIAdgBl
+AHIwHQYDVR0OBBYEFMAC3UR4FwAdGekbhMgnd6lMejtbMAsGA1UdDwQEAwIFoDAT
+BgNVHSUEDDAKBggrBgEFBQcDATAJBgNVHRMEAjAAMIG/BgNVHQEEgbcwgbSAFGfF
+6xihk+gJJ5TfwvtWe1UFnHLQoYGRMIGOMYGLMIGIBgNVBAMegYAATQBpAGMAcgBv
+AHMAbwBmAHQAIABGAG8AcgBlAGYAcgBvAG4AdAAgAFQATQBHACAASABUAFQAUABT
+ACAASQBuAHMAcABlAGMAdABpAG8AbgAgAEMAZQByAHQAaQBmAGkAYwBhAHQAaQBv
+AG4AIABBAHUAdABoAG8AcgBpAHQAeYIIcKhXEmBXr0IwDQYJKoZIhvcNAQEFBQAD
+ggEBABlSxyCMr3+ANr+WmPSjyN5YCJBgnS0IFCwJAzIYP87bcTye/U8eQ2+E6PqG
+Q7Huj7nfHEw9qnGo+HNyPp1ad3KORzXDb54c6xEoi+DeuPzYHPbn4c3hlH49I0aQ
+eWW2w4RslSWpLvO6Y7Lboyz2/Thk/s2kd4RHxkkWpH2ltPqJuYYg3X6oM5+gIFHJ
+WGnh+ojZ5clKvS5yXh3Wkj78M6sb32KfcBk0Hx6NkCYPt60ODYmWtvqwtw6r73u5
+TnTYWRNvo2svX69TriL+CkHY9O1Hkwf2It5zHl3gNiKTJVaak8AuEz/CKWZneovt
+yYLwhUhg3PX5Co1VKYE+9TxloiE=
+-----END CERTIFICATE-----`
+
+func TestParseUniqueID(t *testing.T) {
+	b, _ := pem.Decode([]byte(uniqueIDPEM))
+	if b == nil {
+		t.Fatalf("couldn't decode test certificate")
+	}
+	cert, err := ParseCertificate(b.Bytes)
+	if err != nil {
+		t.Fatalf("ParseCertificate to failed to parse certificate with unique identifier id: %s", err)
+	}
+	if len(cert.Extensions) != 7 {
+		t.Fatalf("unexpected number of extensions (probably because the extension section was not parsed): got %d, want 7", len(cert.Extensions))
+	}
+}
+
+func TestDisableSHA1ForCertOnly(t *testing.T) {
+	t.Setenv("GODEBUG", "")
+
+	tmpl := &Certificate{
+		SerialNumber:          big.NewInt(1),
+		NotBefore:             time.Now().Add(-time.Hour),
+		NotAfter:              time.Now().Add(time.Hour),
+		SignatureAlgorithm:    SHA1WithRSA,
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+		KeyUsage:              KeyUsageCertSign | KeyUsageCRLSign,
+	}
+	certDER, err := CreateCertificate(rand.Reader, tmpl, tmpl, rsaPrivateKey.Public(), rsaPrivateKey)
+	if err != nil {
+		t.Fatalf("failed to generate test cert: %s", err)
+	}
+	cert, err := ParseCertificate(certDER)
+	if err != nil {
+		t.Fatalf("failed to parse test cert: %s", err)
+	}
+
+	err = cert.CheckSignatureFrom(cert)
+	if err == nil {
+		t.Error("expected CheckSignatureFrom to fail")
+	} else if _, ok := err.(InsecureAlgorithmError); !ok {
+		t.Errorf("expected InsecureAlgorithmError error, got %T", err)
+	}
+
+	crlDER, err := CreateRevocationList(rand.Reader, &RevocationList{
+		SignatureAlgorithm: SHA1WithRSA,
+		Number:             big.NewInt(1),
+		ThisUpdate:         time.Now().Add(-time.Hour),
+		NextUpdate:         time.Now().Add(time.Hour),
+	}, cert, rsaPrivateKey)
+	if err != nil {
+		t.Fatalf("failed to generate test CRL: %s", err)
+	}
+	crl, err := ParseRevocationList(crlDER)
+	if err != nil {
+		t.Fatalf("failed to parse test CRL: %s", err)
+	}
+
+	if err = crl.CheckSignatureFrom(cert); err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+
+	// This is an unrelated OCSP response, which will fail signature verification
+	// but shouldn't return a InsecureAlgorithmError, since SHA1 should be allowed
+	// for OCSP.
+	ocspTBSHex := "30819fa2160414884451ff502a695e2d88f421bad90cf2cecbea7c180f32303133303631383037323434335a30743072304a300906052b0e03021a0500041448b60d38238df8456e4ee5843ea394111802979f0414884451ff502a695e2d88f421bad90cf2cecbea7c021100f78b13b946fc9635d8ab49de9d2148218000180f32303133303631383037323434335aa011180f32303133303632323037323434335a"
+	ocspTBS, err := hex.DecodeString(ocspTBSHex)
+	if err != nil {
+		t.Fatalf("failed to decode OCSP response TBS hex: %s", err)
+	}
+
+	err = cert.CheckSignature(SHA1WithRSA, ocspTBS, nil)
+	if err != rsa.ErrVerification {
+		t.Errorf("unexpected error: %s", err)
+	}
+}
+
+func TestParseRevocationList(t *testing.T) {
+	derBytes := fromBase64(derCRLBase64)
+	certList, err := ParseRevocationList(derBytes)
+	if err != nil {
+		t.Errorf("error parsing: %s", err)
+		return
+	}
+	numCerts := len(certList.RevokedCertificates)
+	expected := 88
+	if numCerts != expected {
+		t.Errorf("bad number of revoked certificates. got: %d want: %d", numCerts, expected)
+	}
+}
+
+func TestRevocationListCheckSignatureFrom(t *testing.T) {
+	goodKey, err := ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
+	if err != nil {
+		t.Fatalf("failed to generate test key: %s", err)
+	}
+	badKey, err := ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
+	if err != nil {
+		t.Fatalf("failed to generate test key: %s", err)
+	}
+	tests := []struct {
+		name   string
+		issuer *Certificate
+		err    string
+	}{
+		{
+			name: "valid",
+			issuer: &Certificate{
+				Version:               3,
+				BasicConstraintsValid: true,
+				IsCA:                  true,
+				PublicKeyAlgorithm:    ECDSA,
+				PublicKey:             goodKey.Public(),
+			},
+		},
+		{
+			name: "valid, key usage set",
+			issuer: &Certificate{
+				Version:               3,
+				BasicConstraintsValid: true,
+				IsCA:                  true,
+				PublicKeyAlgorithm:    ECDSA,
+				PublicKey:             goodKey.Public(),
+				KeyUsage:              KeyUsageCRLSign,
+			},
+		},
+		{
+			name: "invalid issuer, wrong key usage",
+			issuer: &Certificate{
+				Version:               3,
+				BasicConstraintsValid: true,
+				IsCA:                  true,
+				PublicKeyAlgorithm:    ECDSA,
+				PublicKey:             goodKey.Public(),
+				KeyUsage:              KeyUsageCertSign,
+			},
+			err: "x509: invalid signature: parent certificate cannot sign this kind of certificate",
+		},
+		{
+			name: "invalid issuer, no basic constraints/ca",
+			issuer: &Certificate{
+				Version:            3,
+				PublicKeyAlgorithm: ECDSA,
+				PublicKey:          goodKey.Public(),
+			},
+			err: "x509: invalid signature: parent certificate cannot sign this kind of certificate",
+		},
+		{
+			name: "invalid issuer, unsupported public key type",
+			issuer: &Certificate{
+				Version:               3,
+				BasicConstraintsValid: true,
+				IsCA:                  true,
+				PublicKeyAlgorithm:    UnknownPublicKeyAlgorithm,
+				PublicKey:             goodKey.Public(),
+			},
+			err: "x509: cannot verify signature: algorithm unimplemented",
+		},
+		{
+			name: "wrong key",
+			issuer: &Certificate{
+				Version:               3,
+				BasicConstraintsValid: true,
+				IsCA:                  true,
+				PublicKeyAlgorithm:    ECDSA,
+				PublicKey:             badKey.Public(),
+			},
+			err: "x509: ECDSA verification failure",
+		},
+	}
+
+	crlIssuer := &Certificate{
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+		PublicKeyAlgorithm:    ECDSA,
+		PublicKey:             goodKey.Public(),
+		KeyUsage:              KeyUsageCRLSign,
+		SubjectKeyId:          []byte{1, 2, 3},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			crlDER, err := CreateRevocationList(rand.Reader, &RevocationList{Number: big.NewInt(1)}, crlIssuer, goodKey)
+			if err != nil {
+				t.Fatalf("failed to generate CRL: %s", err)
+			}
+			crl, err := ParseRevocationList(crlDER)
+			if err != nil {
+				t.Fatalf("failed to parse test CRL: %s", err)
+			}
+			err = crl.CheckSignatureFrom(tc.issuer)
+			if err != nil && err.Error() != tc.err {
+				t.Errorf("unexpected error: got %s, want %s", err, tc.err)
+			} else if err == nil && tc.err != "" {
+				t.Errorf("CheckSignatureFrom did not fail: want %s", tc.err)
+			}
+		})
+	}
+}
+
+func TestOmitEmptyExtensions(t *testing.T) {
+	k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	tmpl := &Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: ":)",
+		},
+		NotAfter:  time.Now().Add(time.Hour),
+		NotBefore: time.Now().Add(-time.Hour),
+	}
+	der, err := CreateCertificate(rand.Reader, tmpl, tmpl, k.Public(), k)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	emptyExtSeq := []byte{0xA3, 0x02, 0x30, 0x00}
+	if bytes.Contains(der, emptyExtSeq) {
+		t.Error("DER encoding contains the an empty extensions SEQUENCE")
+	}
+}
+
+var negativeSerialCert = `-----BEGIN CERTIFICATE-----
+MIIBBTCBraADAgECAgH/MAoGCCqGSM49BAMCMA0xCzAJBgNVBAMTAjopMB4XDTIy
+MDQxNDIzNTYwNFoXDTIyMDQxNTAxNTYwNFowDTELMAkGA1UEAxMCOikwWTATBgcq
+hkjOPQIBBggqhkjOPQMBBwNCAAQ9ezsIsj+q17K87z/PXE/rfGRN72P/Wyn5d6oo
+5M0ZbSatuntMvfKdX79CQxXAxN4oXk3Aov4jVSG12AcDI8ShMAoGCCqGSM49BAMC
+A0cAMEQCIBzfBU5eMPT6m5lsR6cXaJILpAaiD9YxOl4v6dT3rzEjAiBHmjnHmAss
+RqUAyJKFzqZxOlK2q4j2IYnuj5+LrLGbQA==
+-----END CERTIFICATE-----`
+
+func TestParseNegativeSerial(t *testing.T) {
+	pemBlock, _ := pem.Decode([]byte(negativeSerialCert))
+	_, err := ParseCertificate(pemBlock.Bytes)
+	if err != nil {
+		t.Fatalf("failed to parse certificate: %s", err)
+	}
+}
+
+func TestCreateNegativeSerial(t *testing.T) {
+	k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	tmpl := &Certificate{
+		SerialNumber: big.NewInt(-1),
+		Subject: pkix.Name{
+			CommonName: ":)",
+		},
+		NotAfter:  time.Now().Add(time.Hour),
+		NotBefore: time.Now().Add(-time.Hour),
+	}
+	expectedErr := "x509: serial number must be positive"
+	_, err = CreateCertificate(rand.Reader, tmpl, tmpl, k.Public(), k)
+	if err == nil || err.Error() != expectedErr {
+		t.Errorf("CreateCertificate returned unexpected error: want %q, got %q", expectedErr, err)
+	}
+}
+
+const dupExtCert = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+func TestDuplicateExtensionsCert(t *testing.T) {
+	b, _ := pem.Decode([]byte(dupExtCert))
+	if b == nil {
+		t.Fatalf("couldn't decode test certificate")
+	}
+	_, err := ParseCertificate(b.Bytes)
+	if err == nil {
+		t.Fatal("ParseCertificate should fail when parsing certificate with duplicate extensions")
+	}
+}
+
+const dupExtCSR = `-----BEGIN CERTIFICATE REQUEST-----
+MIIBczCB3QIBADAPMQ0wCwYDVQQDEwR0ZXN0MIGfMA0GCSqGSIb3DQEBAQUAA4GN
+ADCBiQKBgQC5PbxMGVJ8aLF9lq/EvGObXTRMB7ieiZL9N+DJZg1n/ECCnZLIvYrr
+ZmmDV7YZsClgxKGfjJB0RQFFyZElFM9EfHEs8NJdidDKCRdIhDXQWRyhXKevHvdm
+CQNKzUeoxvdHpU/uscSkw6BgUzPyLyTx9A6ye2ix94z8Y9hGOBO2DQIDAQABoCUw
+IwYJKoZIhvcNAQkOMRYwFDAIBgIqAwQCBQAwCAYCKgMEAgUAMA0GCSqGSIb3DQEB
+CwUAA4GBAHROEsE7URk1knXmBnQtIHwoq663vlMcX3Hes58pUy020rWP8QkocA+X
+VF18/phg3p5ILlS4fcbbP2bEeV0pePo2k00FDPsJEKCBAX2LKxbU7Vp2OuV2HM2+
+VLOVx0i+/Q7fikp3hbN1JwuMTU0v2KL/IKoUcZc02+5xiYrnOIt5
+-----END CERTIFICATE REQUEST-----`
+
+func TestDuplicateExtensionsCSR(t *testing.T) {
+	b, _ := pem.Decode([]byte(dupExtCSR))
+	if b == nil {
+		t.Fatalf("couldn't decode test CSR")
+	}
+	_, err := ParseCertificateRequest(b.Bytes)
+	if err == nil {
+		t.Fatal("ParseCertificateRequest should fail when parsing CSR with duplicate extensions")
+	}
+}
+
+const dupAttCSR = `-----BEGIN CERTIFICATE REQUEST-----
+MIIBbDCB1gIBADAPMQ0wCwYDVQQDEwR0ZXN0MIGfMA0GCSqGSIb3DQEBAQUAA4GN
+ADCBiQKBgQCj5Po3PKO/JNuxr+B+WNfMIzqqYztdlv+mTQhT0jOR5rTkUvxeeHH8
+YclryES2dOISjaUOTmOAr5GQIIdQl4Ql33Cp7ZR/VWcRn+qvTak0Yow+xVsDo0n4
+7IcvvP6CJ7FRoYBUakVczeXLxCjLwdyK16VGJM06eRzDLykPxpPwLQIDAQABoB4w
+DQYCKgMxBwwFdGVzdDEwDQYCKgMxBwwFdGVzdDIwDQYJKoZIhvcNAQELBQADgYEA
+UJ8hsHxtnIeqb2ufHnQFJO+wEJhx2Uxm/BTuzHOeffuQkwATez4skZ7SlX9exgb7
+6jRMRilqb4F7f8w+uDoqxRrA9zc8mwY16zPsyBhRet+ZGbj/ilgvGmtZ21qZZ/FU
+0pJFJIVLM3l49Onr5uIt5+hCWKwHlgE0nGpjKLR3cMg=
+-----END CERTIFICATE REQUEST-----`
+
+func TestDuplicateAttributesCSR(t *testing.T) {
+	b, _ := pem.Decode([]byte(dupAttCSR))
+	if b == nil {
+		t.Fatalf("couldn't decode test CSR")
+	}
+	_, err := ParseCertificateRequest(b.Bytes)
+	if err != nil {
+		t.Fatal("ParseCertificateRequest should succeed when parsing CSR with duplicate attributes")
+	}
+}