Expanding the Monkeysphere
The Monkeysphere currently has implementations that support two popular protocols in use on the internet today:
SSH: Monkeysphere supports the OpenSSH implementation of the Secure Shell protocol, for authenticating both hosts and users.
HTTPS: Monkeysphere supports secure web traffic by allowing users of Mozilla-based browsers (such as Firefox or Iceweasel) to authenticate web sites that are not authenticated by the browser's built-in X.509 verification. This should work with any HTTPS-capable web server.
But there are many protocols and implementations on the 'net that could use the Monkeysphere for key-based authentication but currently do not. Here are some examples of places we think it could be useful. If you can help with these (or suggest others), please pitch in!
HTTPS client authentication: web servers should be able to authenticate clients that use asymmetric crypto. That is, the client holds an RSA secret key, offers a (potentially self-signed) X.509 Cert to the server as part of the TLS handshake, and the server verifies the key material and commonName or subjectAltName in the cert via the OpenPGP web of trust.
Other TLS connections: for example, SMTP services using STARTTLS (server-to-server and client-to-server), IMAP or POP daemons (using STARTTLS or a direct TLS wrapper), LDAP servers (or LDAPS), XMPP connections (client-to-server and server-to-server)
IRC connections: this could be at the TLS layer, or maybe via some exchange with the NickServ?
OTR client-to-client handshakes.
Integration with OpenPGP Certificates for TLS (RFC 5081) -- TLS clients or servers who receive an OpenPGP certificate from their peer should be able to ask some part of the Monkeysphere toolchain if the particular certificate is valid for the connection.