func main() {
flag.Parse()
if *version {
fmt.Println(gogost.Version)
return
}
h := gost34112012256.New()
io.Copy(h, os.Stdin)
fmt.Println(hex.EncodeToString(h.Sum(nil)))
}
// RFC 7836 VKO GOST R 34.10-2012 256-bit key agreement function.
// UKM is user keying material, also called VKO-factor.
func (prv *PrivateKey) KEK2012256(pub *PublicKey, ukm *big.Int) ([]byte, error) {
if prv.mode != Mode2012 {
return nil, errors.New("KEK2012 can not be used in Mode2001")
}
key, err := prv.KEK(pub, ukm)
if err != nil {
return nil, err
}
h := gost34112012256.New()
h.Write(key)
return h.Sum(key[:0]), nil
}