konec allows you to perform general public key cryptography operations (encrypt/decrypt/sign/verify) with your OpenSSH RSA keys.
This is also possible to do with openssl rsautl, but I wanted a simplified interface, so I wrote one in Go. Build/installation instructions are here: https://launchpad.net/konec/+announcement/10904
So what's the point of konec? As I mention in the man page, encrypting with an OpenSSH key is probably most appropriate for publicly posting a nonce or expiring session key to a remote host, because you're using what is otherwise (in OpenSSH) an authentication/identity key. But what about signatures? Signing a message with an SSH host identity seems interesting from a trust perspective.
Edit:
Right now the encryption is rather limited (I'm doing direct RSA-OAEP on the plaintext) so I'm considering adding a wrapped symmetric cipher. Or maybe this is a feature?
What do you think? What features should I add? How would you use konec?
