Abstract: An approach is provided for performing authentication in a communication system. In one embodiment, a key is established with a terminal in a communication network according to a key agreement protocol. The agreed key is tied to an authentication procedure to provide a security association that supports reuse of the key. A master key is generated based on the agreed key. In another embodiment, digest authentication is combined with key exchange parameters (e.g., Diffie-Hellman parameters) in the payload of the digest message, in which a key (e.g., SMEKEY or MN-AAA) is utilized as a password. In yet another embodiment, an authentication algorithm (e.g., Cellular Authentication and Voice Encryption (CAVE)) is employed with a key agreement protocol with conversion functions to support bootstrapping.