mode of operation

A technique for enhancing the effect of a cryptographic algorithm or adapting the algorithm for an application, such as applying a block cipher to a sequence of data blocks or a data stream. (See: CBC, CCM, CMAC, CFB, CTR, ECB, OFB.)

A type of security policy that states the range of classification levels of information that a system is permitted to handle and the range of clearances and authorizations of users who are permitted to access the system. (See: compartmented security mode, controlled security mode, dedicated security mode, multilevel security mode, partitioned security mode, system-high security mode. Compare: protection level.)

IKE refers to its various types of ISAKMP-scripted exchanges of messages as "modes". Among these are the following:

• "Main mode": One of IKE's two phase 1 modes. (See: ISAKMP.)
• "Quick mode": IKE's only phase 2 mode. (See: ISAKMP.)