4 files changed, 848 insertions, 0 deletions
diff --git a/src/crypto/ed25519/ed25519.go b/src/crypto/ed25519/ed25519.go
new file mode 100644
index 0000000..1dda9e5
--- /dev/null
+++ b/src/crypto/ed25519/ed25519.go
@@ -0,0 +1,344 @@
+// Copyright 2016 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 ed25519 implements the Ed25519 signature algorithm. See
+// https://ed25519.cr.yp.to/.
+//
+// These functions are also compatible with the “Ed25519” function defined in
+// RFC 8032. However, unlike RFC 8032's formulation, this package's private key
+// representation includes a public key suffix to make multiple signing
+// operations with the same key more efficient. This package refers to the RFC
+// 8032 private key as the “seed”.
+package ed25519
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/internal/edwards25519"
+	cryptorand "crypto/rand"
+	"crypto/sha512"
+	"crypto/subtle"
+	"errors"
+	"io"
+	"strconv"
+)
+
+const (
+	// PublicKeySize is the size, in bytes, of public keys as used in this package.
+	PublicKeySize = 32
+	// PrivateKeySize is the size, in bytes, of private keys as used in this package.
+	PrivateKeySize = 64
+	// SignatureSize is the size, in bytes, of signatures generated and verified by this package.
+	SignatureSize = 64
+	// SeedSize is the size, in bytes, of private key seeds. These are the private key representations used by RFC 8032.
+	SeedSize = 32
+)
+
+// PublicKey is the type of Ed25519 public keys.
+type PublicKey []byte
+
+// Any methods implemented on PublicKey might need to also be implemented on
+// PrivateKey, as the latter embeds the former and will expose its methods.
+
+// Equal reports whether pub and x have the same value.
+func (pub PublicKey) Equal(x crypto.PublicKey) bool {
+	xx, ok := x.(PublicKey)
+	if !ok {
+		return false
+	}
+	return subtle.ConstantTimeCompare(pub, xx) == 1
+}
+
+// PrivateKey is the type of Ed25519 private keys. It implements [crypto.Signer].
+type PrivateKey []byte
+
+// Public returns the [PublicKey] corresponding to priv.
+func (priv PrivateKey) Public() crypto.PublicKey {
+	publicKey := make([]byte, PublicKeySize)
+	copy(publicKey, priv[32:])
+	return PublicKey(publicKey)
+}
+
+// Equal reports whether priv and x have the same value.
+func (priv PrivateKey) Equal(x crypto.PrivateKey) bool {
+	xx, ok := x.(PrivateKey)
+	if !ok {
+		return false
+	}
+	return subtle.ConstantTimeCompare(priv, xx) == 1
+}
+
+// Seed returns the private key seed corresponding to priv. It is provided for
+// interoperability with RFC 8032. RFC 8032's private keys correspond to seeds
+// in this package.
+func (priv PrivateKey) Seed() []byte {
+	return bytes.Clone(priv[:SeedSize])
+}
+
+// Sign signs the given message with priv. rand is ignored and can be nil.
+//
+// If opts.HashFunc() is [crypto.SHA512], the pre-hashed variant Ed25519ph is used
+// and message is expected to be a SHA-512 hash, otherwise opts.HashFunc() must
+// be [crypto.Hash](0) and the message must not be hashed, as Ed25519 performs two
+// passes over messages to be signed.
+//
+// A value of type [Options] can be used as opts, or crypto.Hash(0) or
+// crypto.SHA512 directly to select plain Ed25519 or Ed25519ph, respectively.
+func (priv PrivateKey) Sign(rand io.Reader, message []byte, opts crypto.SignerOpts) (signature []byte, err error) {
+	hash := opts.HashFunc()
+	context := ""
+	if opts, ok := opts.(*Options); ok {
+		context = opts.Context
+	}
+	switch {
+	case hash == crypto.SHA512: // Ed25519ph
+		if l := len(message); l != sha512.Size {
+			return nil, errors.New("ed25519: bad Ed25519ph message hash length: " + strconv.Itoa(l))
+		}
+		if l := len(context); l > 255 {
+			return nil, errors.New("ed25519: bad Ed25519ph context length: " + strconv.Itoa(l))
+		}
+		signature := make([]byte, SignatureSize)
+		sign(signature, priv, message, domPrefixPh, context)
+		return signature, nil
+	case hash == crypto.Hash(0) && context != "": // Ed25519ctx
+		if l := len(context); l > 255 {
+			return nil, errors.New("ed25519: bad Ed25519ctx context length: " + strconv.Itoa(l))
+		}
+		signature := make([]byte, SignatureSize)
+		sign(signature, priv, message, domPrefixCtx, context)
+		return signature, nil
+	case hash == crypto.Hash(0): // Ed25519
+		return Sign(priv, message), nil
+	default:
+		return nil, errors.New("ed25519: expected opts.HashFunc() zero (unhashed message, for standard Ed25519) or SHA-512 (for Ed25519ph)")
+	}
+}
+
+// Options can be used with [PrivateKey.Sign] or [VerifyWithOptions]
+// to select Ed25519 variants.
+type Options struct {
+	// Hash can be zero for regular Ed25519, or crypto.SHA512 for Ed25519ph.
+	Hash crypto.Hash
+
+	// Context, if not empty, selects Ed25519ctx or provides the context string
+	// for Ed25519ph. It can be at most 255 bytes in length.
+	Context string
+}
+
+// HashFunc returns o.Hash.
+func (o *Options) HashFunc() crypto.Hash { return o.Hash }
+
+// GenerateKey generates a public/private key pair using entropy from rand.
+// If rand is nil, [crypto/rand.Reader] will be used.
+//
+// The output of this function is deterministic, and equivalent to reading
+// [SeedSize] bytes from rand, and passing them to [NewKeyFromSeed].
+func GenerateKey(rand io.Reader) (PublicKey, PrivateKey, error) {
+	if rand == nil {
+		rand = cryptorand.Reader
+	}
+
+	seed := make([]byte, SeedSize)
+	if _, err := io.ReadFull(rand, seed); err != nil {
+		return nil, nil, err
+	}
+
+	privateKey := NewKeyFromSeed(seed)
+	publicKey := make([]byte, PublicKeySize)
+	copy(publicKey, privateKey[32:])
+
+	return publicKey, privateKey, nil
+}
+
+// NewKeyFromSeed calculates a private key from a seed. It will panic if
+// len(seed) is not [SeedSize]. This function is provided for interoperability
+// with RFC 8032. RFC 8032's private keys correspond to seeds in this
+// package.
+func NewKeyFromSeed(seed []byte) PrivateKey {
+	// Outline the function body so that the returned key can be stack-allocated.
+	privateKey := make([]byte, PrivateKeySize)
+	newKeyFromSeed(privateKey, seed)
+	return privateKey
+}
+
+func newKeyFromSeed(privateKey, seed []byte) {
+	if l := len(seed); l != SeedSize {
+		panic("ed25519: bad seed length: " + strconv.Itoa(l))
+	}
+
+	h := sha512.Sum512(seed)
+	s, err := edwards25519.NewScalar().SetBytesWithClamping(h[:32])
+	if err != nil {
+		panic("ed25519: internal error: setting scalar failed")
+	}
+	A := (&edwards25519.Point{}).ScalarBaseMult(s)
+
+	publicKey := A.Bytes()
+
+	copy(privateKey, seed)
+	copy(privateKey[32:], publicKey)
+}
+
+// Sign signs the message with privateKey and returns a signature. It will
+// panic if len(privateKey) is not [PrivateKeySize].
+func Sign(privateKey PrivateKey, message []byte) []byte {
+	// Outline the function body so that the returned signature can be
+	// stack-allocated.
+	signature := make([]byte, SignatureSize)
+	sign(signature, privateKey, message, domPrefixPure, "")
+	return signature
+}
+
+// Domain separation prefixes used to disambiguate Ed25519/Ed25519ph/Ed25519ctx.
+// See RFC 8032, Section 2 and Section 5.1.
+const (
+	// domPrefixPure is empty for pure Ed25519.
+	domPrefixPure = ""
+	// domPrefixPh is dom2(phflag=1) for Ed25519ph. It must be followed by the
+	// uint8-length prefixed context.
+	domPrefixPh = "SigEd25519 no Ed25519 collisions\x01"
+	// domPrefixCtx is dom2(phflag=0) for Ed25519ctx. It must be followed by the
+	// uint8-length prefixed context.
+	domPrefixCtx = "SigEd25519 no Ed25519 collisions\x00"
+)
+
+func sign(signature, privateKey, message []byte, domPrefix, context string) {
+	if l := len(privateKey); l != PrivateKeySize {
+		panic("ed25519: bad private key length: " + strconv.Itoa(l))
+	}
+	seed, publicKey := privateKey[:SeedSize], privateKey[SeedSize:]
+
+	h := sha512.Sum512(seed)
+	s, err := edwards25519.NewScalar().SetBytesWithClamping(h[:32])
+	if err != nil {
+		panic("ed25519: internal error: setting scalar failed")
+	}
+	prefix := h[32:]
+
+	mh := sha512.New()
+	if domPrefix != domPrefixPure {
+		mh.Write([]byte(domPrefix))
+		mh.Write([]byte{byte(len(context))})
+		mh.Write([]byte(context))
+	}
+	mh.Write(prefix)
+	mh.Write(message)
+	messageDigest := make([]byte, 0, sha512.Size)
+	messageDigest = mh.Sum(messageDigest)
+	r, err := edwards25519.NewScalar().SetUniformBytes(messageDigest)
+	if err != nil {
+		panic("ed25519: internal error: setting scalar failed")
+	}
+
+	R := (&edwards25519.Point{}).ScalarBaseMult(r)
+
+	kh := sha512.New()
+	if domPrefix != domPrefixPure {
+		kh.Write([]byte(domPrefix))
+		kh.Write([]byte{byte(len(context))})
+		kh.Write([]byte(context))
+	}
+	kh.Write(R.Bytes())
+	kh.Write(publicKey)
+	kh.Write(message)
+	hramDigest := make([]byte, 0, sha512.Size)
+	hramDigest = kh.Sum(hramDigest)
+	k, err := edwards25519.NewScalar().SetUniformBytes(hramDigest)
+	if err != nil {
+		panic("ed25519: internal error: setting scalar failed")
+	}
+
+	S := edwards25519.NewScalar().MultiplyAdd(k, s, r)
+
+	copy(signature[:32], R.Bytes())
+	copy(signature[32:], S.Bytes())
+}
+
+// Verify reports whether sig is a valid signature of message by publicKey. It
+// will panic if len(publicKey) is not [PublicKeySize].
+func Verify(publicKey PublicKey, message, sig []byte) bool {
+	return verify(publicKey, message, sig, domPrefixPure, "")
+}
+
+// VerifyWithOptions reports whether sig is a valid signature of message by
+// publicKey. A valid signature is indicated by returning a nil error. It will
+// panic if len(publicKey) is not [PublicKeySize].
+//
+// If opts.Hash is [crypto.SHA512], the pre-hashed variant Ed25519ph is used and
+// message is expected to be a SHA-512 hash, otherwise opts.Hash must be
+// [crypto.Hash](0) and the message must not be hashed, as Ed25519 performs two
+// passes over messages to be signed.
+func VerifyWithOptions(publicKey PublicKey, message, sig []byte, opts *Options) error {
+	switch {
+	case opts.Hash == crypto.SHA512: // Ed25519ph
+		if l := len(message); l != sha512.Size {
+			return errors.New("ed25519: bad Ed25519ph message hash length: " + strconv.Itoa(l))
+		}
+		if l := len(opts.Context); l > 255 {
+			return errors.New("ed25519: bad Ed25519ph context length: " + strconv.Itoa(l))
+		}
+		if !verify(publicKey, message, sig, domPrefixPh, opts.Context) {
+			return errors.New("ed25519: invalid signature")
+		}
+		return nil
+	case opts.Hash == crypto.Hash(0) && opts.Context != "": // Ed25519ctx
+		if l := len(opts.Context); l > 255 {
+			return errors.New("ed25519: bad Ed25519ctx context length: " + strconv.Itoa(l))
+		}
+		if !verify(publicKey, message, sig, domPrefixCtx, opts.Context) {
+			return errors.New("ed25519: invalid signature")
+		}
+		return nil
+	case opts.Hash == crypto.Hash(0): // Ed25519
+		if !verify(publicKey, message, sig, domPrefixPure, "") {
+			return errors.New("ed25519: invalid signature")
+		}
+		return nil
+	default:
+		return errors.New("ed25519: expected opts.Hash zero (unhashed message, for standard Ed25519) or SHA-512 (for Ed25519ph)")
+	}
+}
+
+func verify(publicKey PublicKey, message, sig []byte, domPrefix, context string) bool {
+	if l := len(publicKey); l != PublicKeySize {
+		panic("ed25519: bad public key length: " + strconv.Itoa(l))
+	}
+
+	if len(sig) != SignatureSize || sig[63]&224 != 0 {
+		return false
+	}
+
+	A, err := (&edwards25519.Point{}).SetBytes(publicKey)
+	if err != nil {
+		return false
+	}
+
+	kh := sha512.New()
+	if domPrefix != domPrefixPure {
+		kh.Write([]byte(domPrefix))
+		kh.Write([]byte{byte(len(context))})
+		kh.Write([]byte(context))
+	}
+	kh.Write(sig[:32])
+	kh.Write(publicKey)
+	kh.Write(message)
+	hramDigest := make([]byte, 0, sha512.Size)
+	hramDigest = kh.Sum(hramDigest)
+	k, err := edwards25519.NewScalar().SetUniformBytes(hramDigest)
+	if err != nil {
+		panic("ed25519: internal error: setting scalar failed")
+	}
+
+	S, err := edwards25519.NewScalar().SetCanonicalBytes(sig[32:])
+	if err != nil {
+		return false
+	}
+
+	// [S]B = R + [k]A --> [k](-A) + [S]B = R
+	minusA := (&edwards25519.Point{}).Negate(A)
+	R := (&edwards25519.Point{}).VarTimeDoubleScalarBaseMult(k, minusA, S)
+
+	return bytes.Equal(sig[:32], R.Bytes())
+}
diff --git a/src/crypto/ed25519/ed25519_test.go b/src/crypto/ed25519/ed25519_test.go
new file mode 100644
index 0000000..47c8698
--- /dev/null
+++ b/src/crypto/ed25519/ed25519_test.go
@@ -0,0 +1,384 @@
+// Copyright 2016 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 ed25519
+
+import (
+	"bufio"
+	"bytes"
+	"compress/gzip"
+	"crypto"
+	"crypto/internal/boring"
+	"crypto/rand"
+	"crypto/sha512"
+	"encoding/hex"
+	"internal/testenv"
+	"log"
+	"os"
+	"strings"
+	"testing"
+)
+
+func Example_ed25519ctx() {
+	pub, priv, err := GenerateKey(nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	msg := []byte("The quick brown fox jumps over the lazy dog")
+
+	sig, err := priv.Sign(nil, msg, &Options{
+		Context: "Example_ed25519ctx",
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if err := VerifyWithOptions(pub, msg, sig, &Options{
+		Context: "Example_ed25519ctx",
+	}); err != nil {
+		log.Fatal("invalid signature")
+	}
+}
+
+type zeroReader struct{}
+
+func (zeroReader) Read(buf []byte) (int, error) {
+	for i := range buf {
+		buf[i] = 0
+	}
+	return len(buf), nil
+}
+
+func TestSignVerify(t *testing.T) {
+	var zero zeroReader
+	public, private, _ := GenerateKey(zero)
+
+	message := []byte("test message")
+	sig := Sign(private, message)
+	if !Verify(public, message, sig) {
+		t.Errorf("valid signature rejected")
+	}
+
+	wrongMessage := []byte("wrong message")
+	if Verify(public, wrongMessage, sig) {
+		t.Errorf("signature of different message accepted")
+	}
+}
+
+func TestSignVerifyHashed(t *testing.T) {
+	// From RFC 8032, Section 7.3
+	key, _ := hex.DecodeString("833fe62409237b9d62ec77587520911e9a759cec1d19755b7da901b96dca3d42ec172b93ad5e563bf4932c70e1245034c35467ef2efd4d64ebf819683467e2bf")
+	expectedSig, _ := hex.DecodeString("98a70222f0b8121aa9d30f813d683f809e462b469c7ff87639499bb94e6dae4131f85042463c2a355a2003d062adf5aaa10b8c61e636062aaad11c2a26083406")
+	message, _ := hex.DecodeString("616263")
+
+	private := PrivateKey(key)
+	public := private.Public().(PublicKey)
+	hash := sha512.Sum512(message)
+	sig, err := private.Sign(nil, hash[:], crypto.SHA512)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(sig, expectedSig) {
+		t.Error("signature doesn't match test vector")
+	}
+	sig, err = private.Sign(nil, hash[:], &Options{Hash: crypto.SHA512})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(sig, expectedSig) {
+		t.Error("signature doesn't match test vector")
+	}
+	if err := VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA512}); err != nil {
+		t.Errorf("valid signature rejected: %v", err)
+	}
+
+	if err := VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA256}); err == nil {
+		t.Errorf("expected error for wrong hash")
+	}
+
+	wrongHash := sha512.Sum512([]byte("wrong message"))
+	if VerifyWithOptions(public, wrongHash[:], sig, &Options{Hash: crypto.SHA512}) == nil {
+		t.Errorf("signature of different message accepted")
+	}
+
+	sig[0] ^= 0xff
+	if VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA512}) == nil {
+		t.Errorf("invalid signature accepted")
+	}
+	sig[0] ^= 0xff
+	sig[SignatureSize-1] ^= 0xff
+	if VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA512}) == nil {
+		t.Errorf("invalid signature accepted")
+	}
+
+	// The RFC provides no test vectors for Ed25519ph with context, so just sign
+	// and verify something.
+	sig, err = private.Sign(nil, hash[:], &Options{Hash: crypto.SHA512, Context: "123"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA512, Context: "123"}); err != nil {
+		t.Errorf("valid signature rejected: %v", err)
+	}
+	if err := VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA512, Context: "321"}); err == nil {
+		t.Errorf("expected error for wrong context")
+	}
+	if err := VerifyWithOptions(public, hash[:], sig, &Options{Hash: crypto.SHA256, Context: "123"}); err == nil {
+		t.Errorf("expected error for wrong hash")
+	}
+}
+
+func TestSignVerifyContext(t *testing.T) {
+	// From RFC 8032, Section 7.2
+	key, _ := hex.DecodeString("0305334e381af78f141cb666f6199f57bc3495335a256a95bd2a55bf546663f6dfc9425e4f968f7f0c29f0259cf5f9aed6851c2bb4ad8bfb860cfee0ab248292")
+	expectedSig, _ := hex.DecodeString("55a4cc2f70a54e04288c5f4cd1e45a7bb520b36292911876cada7323198dd87a8b36950b95130022907a7fb7c4e9b2d5f6cca685a587b4b21f4b888e4e7edb0d")
+	message, _ := hex.DecodeString("f726936d19c800494e3fdaff20b276a8")
+	context := "foo"
+
+	private := PrivateKey(key)
+	public := private.Public().(PublicKey)
+	sig, err := private.Sign(nil, message, &Options{Context: context})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(sig, expectedSig) {
+		t.Error("signature doesn't match test vector")
+	}
+	if err := VerifyWithOptions(public, message, sig, &Options{Context: context}); err != nil {
+		t.Errorf("valid signature rejected: %v", err)
+	}
+
+	if VerifyWithOptions(public, []byte("bar"), sig, &Options{Context: context}) == nil {
+		t.Errorf("signature of different message accepted")
+	}
+	if VerifyWithOptions(public, message, sig, &Options{Context: "bar"}) == nil {
+		t.Errorf("signature with different context accepted")
+	}
+
+	sig[0] ^= 0xff
+	if VerifyWithOptions(public, message, sig, &Options{Context: context}) == nil {
+		t.Errorf("invalid signature accepted")
+	}
+	sig[0] ^= 0xff
+	sig[SignatureSize-1] ^= 0xff
+	if VerifyWithOptions(public, message, sig, &Options{Context: context}) == nil {
+		t.Errorf("invalid signature accepted")
+	}
+}
+
+func TestCryptoSigner(t *testing.T) {
+	var zero zeroReader
+	public, private, _ := GenerateKey(zero)
+
+	signer := crypto.Signer(private)
+
+	publicInterface := signer.Public()
+	public2, ok := publicInterface.(PublicKey)
+	if !ok {
+		t.Fatalf("expected PublicKey from Public() but got %T", publicInterface)
+	}
+
+	if !bytes.Equal(public, public2) {
+		t.Errorf("public keys do not match: original:%x vs Public():%x", public, public2)
+	}
+
+	message := []byte("message")
+	var noHash crypto.Hash
+	signature, err := signer.Sign(zero, message, noHash)
+	if err != nil {
+		t.Fatalf("error from Sign(): %s", err)
+	}
+
+	signature2, err := signer.Sign(zero, message, &Options{Hash: noHash})
+	if err != nil {
+		t.Fatalf("error from Sign(): %s", err)
+	}
+	if !bytes.Equal(signature, signature2) {
+		t.Errorf("signatures keys do not match")
+	}
+
+	if !Verify(public, message, signature) {
+		t.Errorf("Verify failed on signature from Sign()")
+	}
+}
+
+func TestEqual(t *testing.T) {
+	public, private, _ := GenerateKey(rand.Reader)
+
+	if !public.Equal(public) {
+		t.Errorf("public key is not equal to itself: %q", public)
+	}
+	if !public.Equal(crypto.Signer(private).Public()) {
+		t.Errorf("private.Public() is not Equal to public: %q", public)
+	}
+	if !private.Equal(private) {
+		t.Errorf("private key is not equal to itself: %q", private)
+	}
+
+	otherPub, otherPriv, _ := GenerateKey(rand.Reader)
+	if public.Equal(otherPub) {
+		t.Errorf("different public keys are Equal")
+	}
+	if private.Equal(otherPriv) {
+		t.Errorf("different private keys are Equal")
+	}
+}
+
+func TestGolden(t *testing.T) {
+	// sign.input.gz is a selection of test cases from
+	// https://ed25519.cr.yp.to/python/sign.input
+	testDataZ, err := os.Open("testdata/sign.input.gz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testDataZ.Close()
+	testData, err := gzip.NewReader(testDataZ)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer testData.Close()
+
+	scanner := bufio.NewScanner(testData)
+	lineNo := 0
+
+	for scanner.Scan() {
+		lineNo++
+
+		line := scanner.Text()
+		parts := strings.Split(line, ":")
+		if len(parts) != 5 {
+			t.Fatalf("bad number of parts on line %d", lineNo)
+		}
+
+		privBytes, _ := hex.DecodeString(parts[0])
+		pubKey, _ := hex.DecodeString(parts[1])
+		msg, _ := hex.DecodeString(parts[2])
+		sig, _ := hex.DecodeString(parts[3])
+		// The signatures in the test vectors also include the message
+		// at the end, but we just want R and S.
+		sig = sig[:SignatureSize]
+
+		if l := len(pubKey); l != PublicKeySize {
+			t.Fatalf("bad public key length on line %d: got %d bytes", lineNo, l)
+		}
+
+		var priv [PrivateKeySize]byte
+		copy(priv[:], privBytes)
+		copy(priv[32:], pubKey)
+
+		sig2 := Sign(priv[:], msg)
+		if !bytes.Equal(sig, sig2[:]) {
+			t.Errorf("different signature result on line %d: %x vs %x", lineNo, sig, sig2)
+		}
+
+		if !Verify(pubKey, msg, sig2) {
+			t.Errorf("signature failed to verify on line %d", lineNo)
+		}
+
+		priv2 := NewKeyFromSeed(priv[:32])
+		if !bytes.Equal(priv[:], priv2) {
+			t.Errorf("recreating key pair gave different private key on line %d: %x vs %x", lineNo, priv[:], priv2)
+		}
+
+		if pubKey2 := priv2.Public().(PublicKey); !bytes.Equal(pubKey, pubKey2) {
+			t.Errorf("recreating key pair gave different public key on line %d: %x vs %x", lineNo, pubKey, pubKey2)
+		}
+
+		if seed := priv2.Seed(); !bytes.Equal(priv[:32], seed) {
+			t.Errorf("recreating key pair gave different seed on line %d: %x vs %x", lineNo, priv[:32], seed)
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		t.Fatalf("error reading test data: %s", err)
+	}
+}
+
+func TestMalleability(t *testing.T) {
+	// https://tools.ietf.org/html/rfc8032#section-5.1.7 adds an additional test
+	// that s be in [0, order). This prevents someone from adding a multiple of
+	// order to s and obtaining a second valid signature for the same message.
+	msg := []byte{0x54, 0x65, 0x73, 0x74}
+	sig := []byte{
+		0x7c, 0x38, 0xe0, 0x26, 0xf2, 0x9e, 0x14, 0xaa, 0xbd, 0x05, 0x9a,
+		0x0f, 0x2d, 0xb8, 0xb0, 0xcd, 0x78, 0x30, 0x40, 0x60, 0x9a, 0x8b,
+		0xe6, 0x84, 0xdb, 0x12, 0xf8, 0x2a, 0x27, 0x77, 0x4a, 0xb0, 0x67,
+		0x65, 0x4b, 0xce, 0x38, 0x32, 0xc2, 0xd7, 0x6f, 0x8f, 0x6f, 0x5d,
+		0xaf, 0xc0, 0x8d, 0x93, 0x39, 0xd4, 0xee, 0xf6, 0x76, 0x57, 0x33,
+		0x36, 0xa5, 0xc5, 0x1e, 0xb6, 0xf9, 0x46, 0xb3, 0x1d,
+	}
+	publicKey := []byte{
+		0x7d, 0x4d, 0x0e, 0x7f, 0x61, 0x53, 0xa6, 0x9b, 0x62, 0x42, 0xb5,
+		0x22, 0xab, 0xbe, 0xe6, 0x85, 0xfd, 0xa4, 0x42, 0x0f, 0x88, 0x34,
+		0xb1, 0x08, 0xc3, 0xbd, 0xae, 0x36, 0x9e, 0xf5, 0x49, 0xfa,
+	}
+
+	if Verify(publicKey, msg, sig) {
+		t.Fatal("non-canonical signature accepted")
+	}
+}
+
+func TestAllocations(t *testing.T) {
+	if boring.Enabled {
+		t.Skip("skipping allocations test with BoringCrypto")
+	}
+	testenv.SkipIfOptimizationOff(t)
+
+	if allocs := testing.AllocsPerRun(100, func() {
+		seed := make([]byte, SeedSize)
+		message := []byte("Hello, world!")
+		priv := NewKeyFromSeed(seed)
+		pub := priv.Public().(PublicKey)
+		signature := Sign(priv, message)
+		if !Verify(pub, message, signature) {
+			t.Fatal("signature didn't verify")
+		}
+	}); allocs > 0 {
+		t.Errorf("expected zero allocations, got %0.1f", allocs)
+	}
+}
+
+func BenchmarkKeyGeneration(b *testing.B) {
+	var zero zeroReader
+	for i := 0; i < b.N; i++ {
+		if _, _, err := GenerateKey(zero); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkNewKeyFromSeed(b *testing.B) {
+	seed := make([]byte, SeedSize)
+	for i := 0; i < b.N; i++ {
+		_ = NewKeyFromSeed(seed)
+	}
+}
+
+func BenchmarkSigning(b *testing.B) {
+	var zero zeroReader
+	_, priv, err := GenerateKey(zero)
+	if err != nil {
+		b.Fatal(err)
+	}
+	message := []byte("Hello, world!")
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Sign(priv, message)
+	}
+}
+
+func BenchmarkVerification(b *testing.B) {
+	var zero zeroReader
+	pub, priv, err := GenerateKey(zero)
+	if err != nil {
+		b.Fatal(err)
+	}
+	message := []byte("Hello, world!")
+	signature := Sign(priv, message)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Verify(pub, message, signature)
+	}
+}
diff --git a/src/crypto/ed25519/ed25519vectors_test.go b/src/crypto/ed25519/ed25519vectors_test.go
new file mode 100644
index 0000000..f933f28
--- /dev/null
+++ b/src/crypto/ed25519/ed25519vectors_test.go
@@ -0,0 +1,120 @@
+// Copyright 2021 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 ed25519_test
+
+import (
+	"crypto/ed25519"
+	"encoding/hex"
+	"encoding/json"
+	"internal/testenv"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+// TestEd25519Vectors runs a very large set of test vectors that exercise all
+// combinations of low-order points, low-order components, and non-canonical
+// encodings. These vectors lock in unspecified and spec-divergent behaviors in
+// edge cases that are not security relevant in most contexts, but that can
+// cause issues in consensus applications if changed.
+//
+// Our behavior matches the "classic" unwritten verification rules of the
+// "ref10" reference implementation.
+//
+// Note that although we test for these edge cases, they are not covered by the
+// Go 1 Compatibility Promise. Applications that need stable verification rules
+// should use github.com/hdevalence/ed25519consensus.
+//
+// See https://hdevalence.ca/blog/2020-10-04-its-25519am for more details.
+func TestEd25519Vectors(t *testing.T) {
+	jsonVectors := downloadEd25519Vectors(t)
+	var vectors []struct {
+		A, R, S, M string
+		Flags      []string
+	}
+	if err := json.Unmarshal(jsonVectors, &vectors); err != nil {
+		t.Fatal(err)
+	}
+	for i, v := range vectors {
+		expectedToVerify := true
+		for _, f := range v.Flags {
+			switch f {
+			// We use the simplified verification formula that doesn't multiply
+			// by the cofactor, so any low order residue will cause the
+			// signature not to verify.
+			//
+			// This is allowed, but not required, by RFC 8032.
+			case "LowOrderResidue":
+				expectedToVerify = false
+			// Our point decoding allows non-canonical encodings (in violation
+			// of RFC 8032) but R is not decoded: instead, R is recomputed and
+			// compared bytewise against the canonical encoding.
+			case "NonCanonicalR":
+				expectedToVerify = false
+			}
+		}
+
+		publicKey := decodeHex(t, v.A)
+		signature := append(decodeHex(t, v.R), decodeHex(t, v.S)...)
+		message := []byte(v.M)
+
+		didVerify := ed25519.Verify(publicKey, message, signature)
+		if didVerify && !expectedToVerify {
+			t.Errorf("#%d: vector with flags %s unexpectedly verified", i, v.Flags)
+		}
+		if !didVerify && expectedToVerify {
+			t.Errorf("#%d: vector with flags %s unexpectedly rejected", i, v.Flags)
+		}
+	}
+}
+
+func downloadEd25519Vectors(t *testing.T) []byte {
+	testenv.MustHaveExternalNetwork(t)
+
+	// Create a temp dir and modcache subdir.
+	d := t.TempDir()
+	// Create a spot for the modcache.
+	modcache := filepath.Join(d, "modcache")
+	if err := os.Mkdir(modcache, 0777); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Setenv("GO111MODULE", "on")
+	t.Setenv("GOMODCACHE", modcache)
+
+	// Download the JSON test file from the GOPROXY with `go mod download`,
+	// pinning the version so test and module caching works as expected.
+	goTool := testenv.GoToolPath(t)
+	path := "filippo.io/mostly-harmless/ed25519vectors@v0.0.0-20210322192420-30a2d7243a94"
+	cmd := exec.Command(goTool, "mod", "download", "-modcacherw", "-json", path)
+	// TODO: enable the sumdb once the TryBots proxy supports it.
+	cmd.Env = append(os.Environ(), "GONOSUMDB=*")
+	output, err := cmd.Output()
+	if err != nil {
+		t.Fatalf("failed to run `go mod download -json %s`, output: %s", path, output)
+	}
+	var dm struct {
+		Dir string // absolute path to cached source root directory
+	}
+	if err := json.Unmarshal(output, &dm); err != nil {
+		t.Fatal(err)
+	}
+
+	jsonVectors, err := os.ReadFile(filepath.Join(dm.Dir, "ed25519vectors.json"))
+	if err != nil {
+		t.Fatalf("failed to read ed25519vectors.json: %v", err)
+	}
+	return jsonVectors
+}
+
+func decodeHex(t *testing.T, s string) []byte {
+	t.Helper()
+	b, err := hex.DecodeString(s)
+	if err != nil {
+		t.Errorf("invalid hex: %v", err)
+	}
+	return b
+}
diff --git a/src/crypto/ed25519/testdata/sign.input.gz b/src/crypto/ed25519/testdata/sign.input.gz
new file mode 100644
index 0000000..e6dc728
--- /dev/null
+++ b/src/crypto/ed25519/testdata/sign.input.gz