func (hk *HelloKey) String() string { return rsa64.PrivToBase64(hk.RSAPrivKey()) }
func (cmk *CipherMsgKey) String() string {
return rsa64.PrivToBase64(cmk.rsa)
}
func (sk *SigKey) String() string {
return rsa64.PrivToBase64(sk.RsaPrivKey())
}