parsear.go

func ParseRsaPrivateKeyFromPemStr(privPEM string) (*rsa.PrivateKey, error) {
	block, _ := pem.Decode([]byte(privPEM))
	if block == nil {
		return nil, errors.New("failed to parse PEM block containing the key")
	}

	priv, err := x509.ParsePKCS1PrivateKey(block.Bytes)
	if err != nil {
		return nil, err
	}

	return priv, nil
}

func ParseRsaPublicKeyFromPemStr(pubPEM string) (*rsa.PublicKey, error) {
	block, _ := pem.Decode([]byte(pubPEM))
	if block == nil {
		return nil, errors.New("failed to parse PEM block containing the key")
	}

	pub, err := x509.ParsePKIXPublicKey(block.Bytes)
	if err != nil {
		return nil, err
	}

	switch pub := pub.(type) {
	case *rsa.PublicKey:
		return pub, nil
	default:
		break // fall through
	}
	return nil, errors.New("Key type is not RSA")
}