diff options
Diffstat (limited to 'src/crypto/internal/nistec/fiat/generate.go')
| -rw-r--r-- | src/crypto/internal/nistec/fiat/generate.go | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/src/crypto/internal/nistec/fiat/generate.go b/src/crypto/internal/nistec/fiat/generate.go new file mode 100644 index 0000000..3b97307 --- /dev/null +++ b/src/crypto/internal/nistec/fiat/generate.go @@ -0,0 +1,331 @@ +// 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. + +//go:build ignore + +package main + +import ( + "bytes" + "go/format" + "io" + "log" + "os" + "os/exec" + "text/template" +) + +var curves = []struct { + Element string + Prime string + Prefix string + FiatType string + BytesLen int +}{ + { + Element: "P224Element", + Prime: "2^224 - 2^96 + 1", + Prefix: "p224", + FiatType: "[4]uint64", + BytesLen: 28, + }, + // The P-256 fiat implementation is used only on 32-bit architectures, but + // the uint32 fiat code is for some reason slower than the uint64 one. That + // suggests there is a wide margin for improvement. + { + Element: "P256Element", + Prime: "2^256 - 2^224 + 2^192 + 2^96 - 1", + Prefix: "p256", + FiatType: "[4]uint64", + BytesLen: 32, + }, + { + Element: "P384Element", + Prime: "2^384 - 2^128 - 2^96 + 2^32 - 1", + Prefix: "p384", + FiatType: "[6]uint64", + BytesLen: 48, + }, + // Note that unsaturated_solinas would be about 2x faster than + // word_by_word_montgomery for P-521, but this curve is used rarely enough + // that it's not worth carrying unsaturated_solinas support for it. + { + Element: "P521Element", + Prime: "2^521 - 1", + Prefix: "p521", + FiatType: "[9]uint64", + BytesLen: 66, + }, +} + +func main() { + t := template.Must(template.New("montgomery").Parse(tmplWrapper)) + + tmplAddchainFile, err := os.CreateTemp("", "addchain-template") + if err != nil { + log.Fatal(err) + } + defer os.Remove(tmplAddchainFile.Name()) + if _, err := io.WriteString(tmplAddchainFile, tmplAddchain); err != nil { + log.Fatal(err) + } + if err := tmplAddchainFile.Close(); err != nil { + log.Fatal(err) + } + + for _, c := range curves { + log.Printf("Generating %s.go...", c.Prefix) + f, err := os.Create(c.Prefix + ".go") + if err != nil { + log.Fatal(err) + } + if err := t.Execute(f, c); err != nil { + log.Fatal(err) + } + if err := f.Close(); err != nil { + log.Fatal(err) + } + + log.Printf("Generating %s_fiat64.go...", c.Prefix) + cmd := exec.Command("docker", "run", "--rm", "--entrypoint", "word_by_word_montgomery", + "fiat-crypto:v0.0.9", "--lang", "Go", "--no-wide-int", "--cmovznz-by-mul", + "--relax-primitive-carry-to-bitwidth", "32,64", "--internal-static", + "--public-function-case", "camelCase", "--public-type-case", "camelCase", + "--private-function-case", "camelCase", "--private-type-case", "camelCase", + "--doc-text-before-function-name", "", "--doc-newline-before-package-declaration", + "--doc-prepend-header", "Code generated by Fiat Cryptography. DO NOT EDIT.", + "--package-name", "fiat", "--no-prefix-fiat", c.Prefix, "64", c.Prime, + "mul", "square", "add", "sub", "one", "from_montgomery", "to_montgomery", + "selectznz", "to_bytes", "from_bytes") + cmd.Stderr = os.Stderr + out, err := cmd.Output() + if err != nil { + log.Fatal(err) + } + out, err = format.Source(out) + if err != nil { + log.Fatal(err) + } + if err := os.WriteFile(c.Prefix+"_fiat64.go", out, 0644); err != nil { + log.Fatal(err) + } + + log.Printf("Generating %s_invert.go...", c.Prefix) + f, err = os.CreateTemp("", "addchain-"+c.Prefix) + if err != nil { + log.Fatal(err) + } + defer os.Remove(f.Name()) + cmd = exec.Command("addchain", "search", c.Prime+" - 2") + cmd.Stderr = os.Stderr + cmd.Stdout = f + if err := cmd.Run(); err != nil { + log.Fatal(err) + } + if err := f.Close(); err != nil { + log.Fatal(err) + } + cmd = exec.Command("addchain", "gen", "-tmpl", tmplAddchainFile.Name(), f.Name()) + cmd.Stderr = os.Stderr + out, err = cmd.Output() + if err != nil { + log.Fatal(err) + } + out = bytes.Replace(out, []byte("Element"), []byte(c.Element), -1) + out, err = format.Source(out) + if err != nil { + log.Fatal(err) + } + if err := os.WriteFile(c.Prefix+"_invert.go", out, 0644); err != nil { + log.Fatal(err) + } + } +} + +const tmplWrapper = `// 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. + +// Code generated by generate.go. DO NOT EDIT. + +package fiat + +import ( + "crypto/subtle" + "errors" +) + +// {{ .Element }} is an integer modulo {{ .Prime }}. +// +// The zero value is a valid zero element. +type {{ .Element }} struct { + // Values are represented internally always in the Montgomery domain, and + // converted in Bytes and SetBytes. + x {{ .Prefix }}MontgomeryDomainFieldElement +} + +const {{ .Prefix }}ElementLen = {{ .BytesLen }} + +type {{ .Prefix }}UntypedFieldElement = {{ .FiatType }} + +// One sets e = 1, and returns e. +func (e *{{ .Element }}) One() *{{ .Element }} { + {{ .Prefix }}SetOne(&e.x) + return e +} + +// Equal returns 1 if e == t, and zero otherwise. +func (e *{{ .Element }}) Equal(t *{{ .Element }}) int { + eBytes := e.Bytes() + tBytes := t.Bytes() + return subtle.ConstantTimeCompare(eBytes, tBytes) +} + +var {{ .Prefix }}ZeroEncoding = new({{ .Element }}).Bytes() + +// IsZero returns 1 if e == 0, and zero otherwise. +func (e *{{ .Element }}) IsZero() int { + eBytes := e.Bytes() + return subtle.ConstantTimeCompare(eBytes, {{ .Prefix }}ZeroEncoding) +} + +// Set sets e = t, and returns e. +func (e *{{ .Element }}) Set(t *{{ .Element }}) *{{ .Element }} { + e.x = t.x + return e +} + +// Bytes returns the {{ .BytesLen }}-byte big-endian encoding of e. +func (e *{{ .Element }}) Bytes() []byte { + // This function is outlined to make the allocations inline in the caller + // rather than happen on the heap. + var out [{{ .Prefix }}ElementLen]byte + return e.bytes(&out) +} + +func (e *{{ .Element }}) bytes(out *[{{ .Prefix }}ElementLen]byte) []byte { + var tmp {{ .Prefix }}NonMontgomeryDomainFieldElement + {{ .Prefix }}FromMontgomery(&tmp, &e.x) + {{ .Prefix }}ToBytes(out, (*{{ .Prefix }}UntypedFieldElement)(&tmp)) + {{ .Prefix }}InvertEndianness(out[:]) + return out[:] +} + +// {{ .Prefix }}MinusOneEncoding is the encoding of -1 mod p, so p - 1, the +// highest canonical encoding. It is used by SetBytes to check for non-canonical +// encodings such as p + k, 2p + k, etc. +var {{ .Prefix }}MinusOneEncoding = new({{ .Element }}).Sub( + new({{ .Element }}), new({{ .Element }}).One()).Bytes() + +// SetBytes sets e = v, where v is a big-endian {{ .BytesLen }}-byte encoding, and returns e. +// If v is not {{ .BytesLen }} bytes or it encodes a value higher than {{ .Prime }}, +// SetBytes returns nil and an error, and e is unchanged. +func (e *{{ .Element }}) SetBytes(v []byte) (*{{ .Element }}, error) { + if len(v) != {{ .Prefix }}ElementLen { + return nil, errors.New("invalid {{ .Element }} encoding") + } + for i := range v { + if v[i] < {{ .Prefix }}MinusOneEncoding[i] { + break + } + if v[i] > {{ .Prefix }}MinusOneEncoding[i] { + return nil, errors.New("invalid {{ .Element }} encoding") + } + } + var in [{{ .Prefix }}ElementLen]byte + copy(in[:], v) + {{ .Prefix }}InvertEndianness(in[:]) + var tmp {{ .Prefix }}NonMontgomeryDomainFieldElement + {{ .Prefix }}FromBytes((*{{ .Prefix }}UntypedFieldElement)(&tmp), &in) + {{ .Prefix }}ToMontgomery(&e.x, &tmp) + return e, nil +} + +// Add sets e = t1 + t2, and returns e. +func (e *{{ .Element }}) Add(t1, t2 *{{ .Element }}) *{{ .Element }} { + {{ .Prefix }}Add(&e.x, &t1.x, &t2.x) + return e +} + +// Sub sets e = t1 - t2, and returns e. +func (e *{{ .Element }}) Sub(t1, t2 *{{ .Element }}) *{{ .Element }} { + {{ .Prefix }}Sub(&e.x, &t1.x, &t2.x) + return e +} + +// Mul sets e = t1 * t2, and returns e. +func (e *{{ .Element }}) Mul(t1, t2 *{{ .Element }}) *{{ .Element }} { + {{ .Prefix }}Mul(&e.x, &t1.x, &t2.x) + return e +} + +// Square sets e = t * t, and returns e. +func (e *{{ .Element }}) Square(t *{{ .Element }}) *{{ .Element }} { + {{ .Prefix }}Square(&e.x, &t.x) + return e +} + +// Select sets v to a if cond == 1, and to b if cond == 0. +func (v *{{ .Element }}) Select(a, b *{{ .Element }}, cond int) *{{ .Element }} { + {{ .Prefix }}Selectznz((*{{ .Prefix }}UntypedFieldElement)(&v.x), {{ .Prefix }}Uint1(cond), + (*{{ .Prefix }}UntypedFieldElement)(&b.x), (*{{ .Prefix }}UntypedFieldElement)(&a.x)) + return v +} + +func {{ .Prefix }}InvertEndianness(v []byte) { + for i := 0; i < len(v)/2; i++ { + v[i], v[len(v)-1-i] = v[len(v)-1-i], v[i] + } +} +` + +const tmplAddchain = `// 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. + +// Code generated by {{ .Meta.Name }}. DO NOT EDIT. + +package fiat + +// Invert sets e = 1/x, and returns e. +// +// If x == 0, Invert returns e = 0. +func (e *Element) Invert(x *Element) *Element { + // Inversion is implemented as exponentiation with exponent p − 2. + // The sequence of {{ .Ops.Adds }} multiplications and {{ .Ops.Doubles }} squarings is derived from the + // following addition chain generated with {{ .Meta.Module }} {{ .Meta.ReleaseTag }}. + // + {{- range lines (format .Script) }} + // {{ . }} + {{- end }} + // + + var z = new(Element).Set(e) + {{- range .Program.Temporaries }} + var {{ . }} = new(Element) + {{- end }} + {{ range $i := .Program.Instructions -}} + {{- with add $i.Op }} + {{ $i.Output }}.Mul({{ .X }}, {{ .Y }}) + {{- end -}} + + {{- with double $i.Op }} + {{ $i.Output }}.Square({{ .X }}) + {{- end -}} + + {{- with shift $i.Op -}} + {{- $first := 0 -}} + {{- if ne $i.Output.Identifier .X.Identifier }} + {{ $i.Output }}.Square({{ .X }}) + {{- $first = 1 -}} + {{- end }} + for s := {{ $first }}; s < {{ .S }}; s++ { + {{ $i.Output }}.Square({{ $i.Output }}) + } + {{- end -}} + {{- end }} + + return e.Set(z) +} +` |