Pre-Shared Key Ciphersuites for Transport Layer Security (TLS)

This document specifies three sets of new ciphersuites for the Transport Layer Security (TLS) protocol to support authentication based on pre-shared keys. These pre-shared keys are symmetric keys, shared in advance among the communicating parties. The first set of ciphersuites uses only symmetric key operations for authentication. The second set uses a Diffie-Hellman exchange authenticated with a pre-shared key; and the third set combines public key authentication of the server with pre-shared key authentication of the client.