(1) In Cryptographic Support, a data-encrypting key used to encrypt data before it is sent to another location.
(2) In computer security, a temporary key that grants access to a particular resource or session. A session key is similar to a service ticket in the Kerberos protocol.
(3) A key that uniquely identifies each CICS-IMS session. The session key is formed from the CICS name for the session and the IMS subpool name.