43 lines
950 B
Go
43 lines
950 B
Go
package rfc6979
|
|
|
|
import (
|
|
"crypto/dsa" //nolint:staticcheck
|
|
"hash"
|
|
"math/big"
|
|
)
|
|
|
|
// SignDSA signs an arbitrary length hash (which should be the result of hashing
|
|
// a larger message) using the private key, priv. It returns the signature as a
|
|
// pair of integers.
|
|
//
|
|
// Deprecated: crypto/dsa package is deprecated in Go, so please swtich to ECDSA.
|
|
// This method can be removed in future versions.
|
|
func SignDSA(priv *dsa.PrivateKey, hash []byte, alg func() hash.Hash) (r, s *big.Int, err error) {
|
|
n := priv.Q.BitLen()
|
|
if n&7 != 0 {
|
|
err = dsa.ErrInvalidPublicKey
|
|
return
|
|
}
|
|
|
|
generateSecret(priv.Q, priv.X, alg, hash, func(k *big.Int, z *big.Int, _ []byte) bool {
|
|
r = new(big.Int).Exp(priv.G, k, priv.P)
|
|
r.Mod(r, priv.Q)
|
|
|
|
if r.Sign() == 0 {
|
|
return false
|
|
}
|
|
|
|
inv := k.ModInverse(k, priv.Q)
|
|
|
|
s = new(big.Int).Mul(priv.X, r)
|
|
s.Add(s, z)
|
|
s.Mod(s, priv.Q)
|
|
s.Mul(s, inv)
|
|
s.Mod(s, priv.Q)
|
|
|
|
return s.Sign() != 0
|
|
})
|
|
|
|
return
|
|
}
|