RSA public key signatures does not work

[Troyhy]

Hi,

I just tried to use SignatureAuthentication with ALGORITHM = 'rsa-sha256'.
After debugging around, I found out that build_signature() throws exception "TypeError: Private key not available in this object" in line 70. That is because when using RSA public keys that function should be Verify not sign. Sign expects to have private key and that of course is not available in servers end.