gost3410.Public/Private keys BE/LE marshalling

[gogost.git] / gost3410 / private.go

diff --git a/gost3410/private.go b/gost3410/private.go
index 983d8d2849399c80a5617e8a5917180f9b96eb75..18549a29cf1f0f8718af45fef3059ba0183c7977 100644 (file)
--- a/gost3410/private.go
+++ b/gost3410/private.go
@@ -29,7 +29,7 @@ type PrivateKey struct {
 }
 
 // Unmarshal little-endian private key. "raw" must be c.PointSize() length.
-func NewPrivateKey(c *Curve, raw []byte) (*PrivateKey, error) {
+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)
@@ -45,6 +45,24 @@ func NewPrivateKey(c *Curve, raw []byte) (*PrivateKey, error) {
        return &PrivateKey{c, k.Mod(k, c.Q)}, nil
 }
 
+// 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 {
@@ -54,12 +72,22 @@ func GenPrivateKey(c *Curve, rand io.Reader) (*PrivateKey, error) {
 }
 
 // Marshal little-endian private key. raw will be prv.C.PointSize() length.
-func (prv *PrivateKey) Raw() (raw []byte) {
+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 {