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[gogost.git] / gost3410 / private.go

diff --git a/gost3410/private.go b/gost3410/private.go
index 045c8185b94458e7ad2c9be153bd37eeb99f04ed..4d73b07fc3f652c5c7018cea459503e47029f7f1 100644 (file)
--- a/gost3410/private.go
+++ b/gost3410/private.go
@@ -1,5 +1,5 @@
 // GoGOST -- Pure Go GOST cryptographic functions library
-// Copyright (C) 2015-2019 Sergey Matveev <stargrave@stargrave.org>
+// Copyright (C) 2015-2021 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
@@ -18,41 +18,42 @@ package gost3410
 import (
        "crypto"
        "errors"
+       "fmt"
        "io"
        "math/big"
 )
 
 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, errors.New("Invalid private key length")
+func NewPrivateKey(curve *Curve, raw []byte) (*PrivateKey, error) {
+       pointSize := curve.PointSize()
+       if len(raw) != pointSize {
+               return nil, fmt.Errorf("gogost/gost3410: len(key) != %d", pointSize)
        }
-       key := make([]byte, int(mode))
+       key := make([]byte, pointSize)
        for i := 0; i < len(key); i++ {
                key[i] = raw[len(raw)-i-1]
        }
        k := bytes2big(key)
        if k.Cmp(zero) == 0 {
-               return nil, errors.New("Zero private key")
+               return nil, errors.New("gogost/gost3410: zero private key")
        }
-       return &PrivateKey{curve, mode, k}, nil
+       return &PrivateKey{curve, k}, nil
 }
 
-func GenPrivateKey(curve *Curve, mode Mode, rand io.Reader) (*PrivateKey, error) {
-       raw := make([]byte, int(mode))
+func GenPrivateKey(curve *Curve, rand io.Reader) (*PrivateKey, error) {
+       raw := make([]byte, curve.PointSize())
        if _, err := io.ReadFull(rand, raw); err != nil {
                return nil, err
        }
-       return NewPrivateKey(curve, mode, raw)
+       return NewPrivateKey(curve, raw)
 }
 
 func (prv *PrivateKey) Raw() []byte {
-       raw := pad(prv.Key.Bytes(), int(prv.Mode))
+       raw := pad(prv.Key.Bytes(), prv.C.PointSize())
        reverse(raw)
        return raw
 }
@@ -62,7 +63,7 @@ func (prv *PrivateKey) PublicKey() (*PublicKey, error) {
        if err != nil {
                return nil, 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) {
@@ -71,7 +72,7 @@ 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
@@ -101,9 +102,10 @@ Retry:
        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
 }
 
@@ -118,3 +120,38 @@ func (prv *PrivateKey) Public() crypto.PublicKey {
        }
        return pub
 }
+
+type PrivateKeyReverseDigest struct {
+       Prv *PrivateKey
+}
+
+func (prv *PrivateKeyReverseDigest) Public() crypto.PublicKey {
+       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)
+}
+
+type PrivateKeyReverseDigestAndSignature struct {
+       Prv *PrivateKey
+}
+
+func (prv *PrivateKeyReverseDigestAndSignature) Public() crypto.PublicKey {
+       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)
+       if err != nil {
+               return sign, err
+       }
+       reverse(sign)
+       return sign, err
+}