key.go
func GenerateKeyPair(typ, bits int) (PrivKey, PubKey, error) {
	return GenerateKeyPairWithReader(typ, bits, rand.Reader)
}
func GenerateKeyPair(typ, bits int) (PrivKey, PubKey, error) {
	return GenerateKeyPairWithReader(typ, bits, rand.Reader)
}
// GenerateKeyPair generates a private and public key