http://asg.web.cmu.edu/sasl Utilized by GSI. Open Source Simple Authentication and Security Layer in the C Language.
The Simple Authentication and Security Layer, which is a method for adding authentication services to network protocols in a somewhat generic way. It is also capable of providing key exchange in many circumstances.
See Simple Authentication and Security Layer (SASL)
Simple Authentication and Security Layer, a method for adding authentication support to connection-based protocols. To use SASL, a protocol includes a command for identifying and authenticating a user to a server and for optionally negotiating protection of subsequent protocol interactions. If its use is negotiated, a security layer is inserted between the protocol and the connection.