Authenticated Key Exchange

See also: Key-agreement protocol and Password-authenticated key agreement

Authenticated Key Exchange (AKE), Authenticated Key Agreement (AKA) or Authentication and Key Establishment (AKE) is the exchange or creation of a session key in a key exchange protocol which also authenticates the identities of parties involved in key exchange.^[1] AKE typically occurs at the beginning of a communication session.^[2] Features of AKE protocols include determination of which keys already exist and can be used, how new keys will be generated, and how many users the protocol is applicable to.^[2]

AKE protocols make use of long term keys that exist prior to the protocol, and session keys, which are typically symmetric keys established during the execution of the protocol.^[2] AKE protocols can be divided into four categories, based on the different types of long term keys used:^[2]

1. Pre-shared keys
2. Public–private key pairs
3. Identity-based keys
4. Passwords

The use of Transport Layer Security (TLS) to secure HTTP connections is perhaps the most widely deployed AKE protocol.^[3]