// GoGOST -- Pure Go GOST cryptographic functions library
-// Copyright (C) 2015-2020 Sergey Matveev <stargrave@stargrave.org>
+// Copyright (C) 2015-2024 Sergey Matveev <stargrave@stargrave.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
)
type PrivateKey struct {
- C *Curve
- Mode Mode
- Key *big.Int
+ C *Curve
+ Key *big.Int
}
-func NewPrivateKey(curve *Curve, mode Mode, raw []byte) (*PrivateKey, error) {
- if len(raw) != int(mode) {
- return nil, fmt.Errorf("gogost/gost3410: len(key) != %d", mode)
+// Unmarshal little-endian private key. "raw" must be c.PointSize() length.
+func NewPrivateKeyLE(c *Curve, raw []byte) (*PrivateKey, error) {
+ pointSize := c.PointSize()
+ if len(raw) != pointSize {
+ return nil, fmt.Errorf("gogost/gost3410: len(key)=%d != %d", len(raw), pointSize)
}
- key := make([]byte, int(mode))
+ key := make([]byte, pointSize)
for i := 0; i < len(key); i++ {
key[i] = raw[len(raw)-i-1]
}
if k.Cmp(zero) == 0 {
return nil, errors.New("gogost/gost3410: zero private key")
}
- return &PrivateKey{curve, mode, k}, nil
+ return &PrivateKey{c, k.Mod(k, c.Q)}, nil
}
-func GenPrivateKey(curve *Curve, mode Mode, rand io.Reader) (*PrivateKey, error) {
- raw := make([]byte, int(mode))
+// Unmarshal big-endian private key. "raw" must be c.PointSize() length.
+func NewPrivateKeyBE(c *Curve, raw []byte) (*PrivateKey, error) {
+ pointSize := c.PointSize()
+ if len(raw) != pointSize {
+ return nil, fmt.Errorf("gogost/gost3410: len(key)=%d != %d", len(raw), pointSize)
+ }
+ k := bytes2big(raw)
+ if k.Cmp(zero) == 0 {
+ return nil, errors.New("gogost/gost3410: zero private key")
+ }
+ return &PrivateKey{c, k.Mod(k, c.Q)}, nil
+}
+
+// This is an alias for NewPrivateKeyLE().
+func NewPrivateKey(c *Curve, raw []byte) (*PrivateKey, error) {
+ return NewPrivateKeyLE(c, raw)
+}
+
+func GenPrivateKey(c *Curve, rand io.Reader) (*PrivateKey, error) {
+ raw := make([]byte, c.PointSize())
if _, err := io.ReadFull(rand, raw); err != nil {
- return nil, err
+ return nil, fmt.Errorf("gogost/gost3410.GenPrivateKey: %w", err)
}
- return NewPrivateKey(curve, mode, raw)
+ return NewPrivateKey(c, raw)
}
-func (prv *PrivateKey) Raw() []byte {
- raw := pad(prv.Key.Bytes(), int(prv.Mode))
+// Marshal little-endian private key. raw will be prv.C.PointSize() length.
+func (prv *PrivateKey) RawLE() (raw []byte) {
+ raw = pad(prv.Key.Bytes(), prv.C.PointSize())
reverse(raw)
return raw
}
+// Marshal big-endian private key. raw will be prv.C.PointSize() length.
+func (prv *PrivateKey) RawBE() (raw []byte) {
+ return pad(prv.Key.Bytes(), prv.C.PointSize())
+}
+
+// This is an alias for RawLE().
+func (prv *PrivateKey) Raw() []byte {
+ return prv.RawLE()
+}
+
func (prv *PrivateKey) PublicKey() (*PublicKey, error) {
x, y, err := prv.C.Exp(prv.Key, prv.C.X, prv.C.Y)
if err != nil {
- return nil, err
+ return nil, fmt.Errorf("gogost/gost3410.PrivateKey.PublicKey: %w", err)
}
- return &PublicKey{prv.C, prv.Mode, x, y}, nil
+ return &PublicKey{prv.C, x, y}, nil
}
func (prv *PrivateKey) SignDigest(digest []byte, rand io.Reader) ([]byte, error) {
if e.Cmp(zero) == 0 {
e = big.NewInt(1)
}
- kRaw := make([]byte, int(prv.Mode))
+ kRaw := make([]byte, prv.C.PointSize())
var err error
var k *big.Int
var r *big.Int
s := big.NewInt(0)
Retry:
if _, err = io.ReadFull(rand, kRaw); err != nil {
- return nil, err
+ return nil, fmt.Errorf("gogost/gost3410.PrivateKey.SignDigest: %w", err)
}
k = bytes2big(kRaw)
k.Mod(k, prv.C.Q)
}
r, _, err = prv.C.Exp(k, prv.C.X, prv.C.Y)
if err != nil {
- return nil, err
+ return nil, fmt.Errorf("gogost/gost3410.PrivateKey.SignDigest: %w", err)
}
r.Mod(r, prv.C.Q)
if r.Cmp(zero) == 0 {
if s.Cmp(zero) == 0 {
goto Retry
}
+ pointSize := prv.C.PointSize()
return append(
- pad(s.Bytes(), int(prv.Mode)),
- pad(r.Bytes(), int(prv.Mode))...,
+ pad(s.Bytes(), pointSize),
+ pad(r.Bytes(), pointSize)...,
), nil
}
-func (prv *PrivateKey) Sign(rand io.Reader, digest []byte, opts crypto.SignerOpts) ([]byte, error) {
+// Sign the digest. opts argument is unused. That is identical to SignDigest,
+// but kept to be friendly to crypto.Signer.
+func (prv *PrivateKey) Sign(
+ rand io.Reader, digest []byte, opts crypto.SignerOpts,
+) ([]byte, error) {
return prv.SignDigest(digest, rand)
}
return prv.Prv.Public()
}
-func (prv *PrivateKeyReverseDigest) Sign(rand io.Reader, digest []byte, opts crypto.SignerOpts) ([]byte, error) {
- d := make([]byte, len(digest))
- copy(d, digest)
- reverse(d)
- return prv.Prv.Sign(rand, d, opts)
+func (prv *PrivateKeyReverseDigest) Sign(
+ rand io.Reader, digest []byte, opts crypto.SignerOpts,
+) ([]byte, error) {
+ dgst := make([]byte, len(digest))
+ for i := 0; i < len(digest); i++ {
+ dgst[i] = digest[len(digest)-i-1]
+ }
+ return prv.Prv.Sign(rand, dgst, opts)
}
type PrivateKeyReverseDigestAndSignature struct {
return prv.Prv.Public()
}
-func (prv *PrivateKeyReverseDigestAndSignature) Sign(rand io.Reader, digest []byte, opts crypto.SignerOpts) ([]byte, error) {
- d := make([]byte, len(digest))
- copy(d, digest)
- reverse(d)
- sign, err := prv.Prv.Sign(rand, d, opts)
+func (prv *PrivateKeyReverseDigestAndSignature) Sign(
+ rand io.Reader, digest []byte, opts crypto.SignerOpts,
+) ([]byte, error) {
+ dgst := make([]byte, len(digest))
+ for i := 0; i < len(digest); i++ {
+ dgst[i] = digest[len(digest)-i-1]
+ }
+ sign, err := prv.Prv.Sign(rand, dgst, opts)
if err != nil {
return sign, err
}