crtauth-java is a public key backed client/server authentication system written in Java.

crtauth-java is the Java port of the original crtauth implementation that can be found here. The java implementation is fully wire compatible with the python version.

crtauth itself is a system for authenticating a user to a centralized server. The initial use case is to create a convenient authentication for command line tools that interacts with a central server without resorting to authentication using a shared secret, such as a password.

If you are looking at building a client in Java and would like to connect to a local ssh-agent, here's how:

final AgentSigner signer = new AgentSigner();
final byte[] signed = signer.sign(new byte[] {1, 2, 3, 4}, new Fingerprint(publicKey));

crtauth-java is free software, this code is released under the Apache Software License, version 2. The original code is written by Federico Piccinini with contributions from Noa Resare, John-John Tedro, Martin Parm and Nic Cope.

All code is Copyright (c) 2015 Spotify AB