scope:

This document establishes five modes of operation for applications of an n-bit block cipher (e.g. protection of data during transmission or in storage). The defined modes only provide protection of data confidentiality. Protection of data integrity is not within the scope of this document. Also, most modes do not protect the confidentiality of message length information.

NOTE 1 Methods for protecting the integrity of data using a block cipher are provided in ISO/IEC 9797-1.

NOTE 2 Methods for simultaneously protecting the confidentiality and integrity of data are provided in ISO/IEC 19772.

This document specifies the modes of operation and gives recommendations for choosing values of parameters (as appropriate).

NOTE 3 The modes of operation specified in this document have been assigned object identifiers in accordance with ISO/IEC 9834. The list of assigned object identifiers is given in Annex A. In applications in which object identifiers are used, the object identifiers specified in Annex A are to be used in preference to any other object identifiers that can exist for the mode concerned.

NOTE 4 Annex B contains comments on the properties of each mode and important security guidance.