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[gogost.git] / gost3410 / public.go

diff --git a/gost3410/public.go b/gost3410/public.go
index de2d858c604d793d559c5b11fcdab47fdcc04761..a8669cf38075ee436b8c5767122aa0898a25fb4a 100644 (file)
--- a/gost3410/public.go
+++ b/gost3410/public.go
@@ -1,5 +1,5 @@
 // GoGOST -- Pure Go GOST cryptographic functions library
-// Copyright (C) 2015-2019 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
@@ -16,19 +16,20 @@
 package gost3410
 
 import (
+       "crypto"
        "fmt"
        "math/big"
 )
 
 type PublicKey struct {
        C    *Curve
-       Mode Mode
-       X    *big.Int
-       Y    *big.Int
+       X, Y *big.Int
 }
 
-func NewPublicKey(curve *Curve, mode Mode, raw []byte) (*PublicKey, error) {
-       key := make([]byte, 2*int(mode))
+// Unmarshal LE(X)||LE(Y) public key. "raw" must be 2*c.PointSize() length.
+func NewPublicKeyLE(c *Curve, raw []byte) (*PublicKey, error) {
+       pointSize := c.PointSize()
+       key := make([]byte, 2*pointSize)
        if len(raw) != len(key) {
                return nil, fmt.Errorf("gogost/gost3410: len(key) != %d", len(key))
        }
@@ -36,28 +37,62 @@ func NewPublicKey(curve *Curve, mode Mode, raw []byte) (*PublicKey, error) {
                key[i] = raw[len(raw)-i-1]
        }
        return &PublicKey{
-               curve,
-               mode,
-               bytes2big(key[int(mode) : 2*int(mode)]),
-               bytes2big(key[:int(mode)]),
+               c,
+               bytes2big(key[pointSize : 2*pointSize]),
+               bytes2big(key[:pointSize]),
        }, nil
 }
 
-func (pub *PublicKey) Raw() []byte {
+// Unmarshal BE(X)||BE(Y) public key. "raw" must be 2*c.PointSize() length.
+func NewPublicKeyBE(c *Curve, raw []byte) (*PublicKey, error) {
+       pointSize := c.PointSize()
+       if len(raw) != 2*pointSize {
+               return nil, fmt.Errorf("gogost/gost3410: len(key) != %d", 2*pointSize)
+       }
+       return &PublicKey{
+               c,
+               bytes2big(raw[:pointSize]),
+               bytes2big(raw[pointSize:]),
+       }, nil
+}
+
+// This is an alias for NewPublicKeyLE().
+func NewPublicKey(c *Curve, raw []byte) (*PublicKey, error) {
+       return NewPublicKeyLE(c, raw)
+}
+
+// Marshal LE(X)||LE(Y) public key. raw will be 2*pub.C.PointSize() length.
+func (pub *PublicKey) RawLE() []byte {
+       pointSize := pub.C.PointSize()
        raw := append(
-               pad(pub.Y.Bytes(), int(pub.Mode)),
-               pad(pub.X.Bytes(), int(pub.Mode))...,
+               pad(pub.Y.Bytes(), pointSize),
+               pad(pub.X.Bytes(), pointSize)...,
        )
        reverse(raw)
        return raw
 }
 
+// Marshal BE(X)||BE(Y) public key. raw will be 2*pub.C.PointSize() length.
+func (pub *PublicKey) RawBE() []byte {
+       pointSize := pub.C.PointSize()
+       return append(
+               pad(pub.X.Bytes(), pointSize),
+               pad(pub.Y.Bytes(), pointSize)...,
+       )
+}
+
+// This is an alias for RawLE().
+func (pub *PublicKey) Raw() []byte {
+       return pub.RawLE()
+}
+
 func (pub *PublicKey) VerifyDigest(digest, signature []byte) (bool, error) {
-       if len(signature) != 2*int(pub.Mode) {
-               return false, fmt.Errorf("gogost/gost3410: len(signature) != %d", 2*int(pub.Mode))
+       pointSize := pub.C.PointSize()
+       if len(signature) != 2*pointSize {
+               return false, fmt.Errorf("gogost/gost3410: len(signature)=%d != %d", len(signature), 2*pointSize)
        }
-       s := bytes2big(signature[:pub.Mode])
-       r := bytes2big(signature[pub.Mode:])
+       s := bytes2big(signature[:pointSize])
+       r := bytes2big(signature[pointSize:])
        if r.Cmp(zero) <= 0 ||
                r.Cmp(pub.C.Q) >= 0 ||
                s.Cmp(zero) <= 0 ||
@@ -106,3 +141,51 @@ func (pub *PublicKey) VerifyDigest(digest, signature []byte) (bool, error) {
        lm.Mod(lm, pub.C.Q)
        return lm.Cmp(r) == 0, nil
 }
+
+func (our *PublicKey) Equal(theirKey crypto.PublicKey) bool {
+       their, ok := theirKey.(*PublicKey)
+       if !ok {
+               return false
+       }
+       return our.X.Cmp(their.X) == 0 && our.Y.Cmp(their.Y) == 0 && our.C.Equal(their.C)
+}
+
+type PublicKeyReverseDigest struct {
+       Pub *PublicKey
+}
+
+func (pub PublicKeyReverseDigest) VerifyDigest(
+       digest, signature []byte,
+) (bool, error) {
+       dgst := make([]byte, len(digest))
+       for i := 0; i < len(digest); i++ {
+               dgst[i] = digest[len(digest)-i-1]
+       }
+       return pub.Pub.VerifyDigest(dgst, signature)
+}
+
+func (pub PublicKeyReverseDigest) Equal(theirKey crypto.PublicKey) bool {
+       return pub.Pub.Equal(theirKey)
+}
+
+type PublicKeyReverseDigestAndSignature struct {
+       Pub *PublicKey
+}
+
+func (pub PublicKeyReverseDigestAndSignature) VerifyDigest(
+       digest, signature []byte,
+) (bool, error) {
+       dgst := make([]byte, len(digest))
+       for i := 0; i < len(digest); i++ {
+               dgst[i] = digest[len(digest)-i-1]
+       }
+       sign := make([]byte, len(signature))
+       for i := 0; i < len(signature); i++ {
+               sign[i] = signature[len(signature)-i-1]
+       }
+       return pub.Pub.VerifyDigest(dgst, sign)
+}
+
+func (pub PublicKeyReverseDigestAndSignature) Equal(theirKey crypto.PublicKey) bool {
+       return pub.Pub.Equal(theirKey)
+}