// GoGOST -- Pure Go GOST cryptographic functions library
-// Copyright (C) 2015-2020 Sergey Matveev <stargrave@stargrave.org>
+// Copyright (C) 2015-2023 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
package gost3410
import (
+ "fmt"
"math/big"
)
func (prv *PrivateKey) KEK(pub *PublicKey, ukm *big.Int) ([]byte, error) {
keyX, keyY, err := prv.C.Exp(prv.Key, pub.X, pub.Y)
if err != nil {
- return nil, err
+ return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK: %w", err)
}
- ukm = ukm.Mul(ukm, prv.C.Co)
- if ukm.Cmp(bigInt1) != 0 {
- keyX, keyY, err = prv.C.Exp(ukm, keyX, keyY)
+ u := big.NewInt(0).Set(ukm).Mul(ukm, prv.C.Co)
+ if u.Cmp(bigInt1) != 0 {
+ keyX, keyY, err = prv.C.Exp(u, keyX, keyY)
if err != nil {
- return nil, err
+ return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK: %w", err)
}
}
- pk := PublicKey{prv.C, prv.Mode, keyX, keyY}
+ pk := PublicKey{prv.C, keyX, keyY}
return pk.Raw(), nil
}