如何使用tls cert和key创建PGP密钥，以及如何使用PGP私钥在golang中解密PGP消息？

started with the following logic,

(based on: RSA key part is common for TLS and PGP)

tlsCert, err := tls.LoadX509KeyPair(certFilePath, keyFilePath)
if err != nil {
    return
}
certx509, _ := ioutil.ReadFile(certFilePath)

block, _ := pem.Decode([]byte(certx509))
certTest, err := x509.ParseCertificate(block.Bytes)
if err != nil {
    return
}

privateKeyTest := tlsCert.PrivateKey

config = &packet.Config{}
config.DefaultCompressionAlgo = 1
config.DefaultCipher = 9
config.DefaultHash = 3
entity, _ = openpgp.NewEntity("", "", "", config)
entity.PrimaryKey.PublicKey = (certTest.PublicKey).(*rsa.PublicKey)
entity.PrivateKey.PrivateKey = privateKeyTest.(*rsa.PrivateKey)

entitylist := make(openpgp.EntityList, 1)
entitylist[0] = entity

md, err := openpgp.ReadMessage(encryptedmessagebytes, entitylist , nil, config)

openpgp.ReadMessage returns the following error

openpgp: invalid data: tag byte does not have MSB set

I think I'm missing something while creating the entity. Can you please help me with this?