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CCM mode (Counter with CBC-MAC) is a mode of operation for cryptographic block ciphers. It is an authenticated encryption algorithm designed to provide both authentication and privacy. CCM mode is only defined for 128-bit block ciphers. In RFC 3610, it is defined for use with 128-bit AES. This article does not cite its references or sources. ...
In cryptography, a block cipher operates on blocks of fixed length, often 64 or 128 bits. ...
In cryptography, a block cipher is a symmetric key cipher which operates on fixed-length groups of bits, termed blocks, with an unvarying transformation. ...
Authenticated Encryption (AE) is a term used to describe encryption systems which simultaneously protect privacy and authenticity. ...
Authentication is the act of establishing or confirming something or someone as authentic. ...
Privacy is the ability of an individual or group to stop information about themselves from becoming known to people other than those they choose to give the information to. ...
General Designer(s) Vincent Rijmen and Joan Daemen First published 1998 Derived from Square (cipher) Cipher(s) based on this design Crypton (cypher), Anubis (cipher), GRAND CRU Algorithm detail Block size(s) 128 bits note Key size(s) 128, 192 or 256 bits note Structure Substitution-permutation network Number of...
Encryption and authentication
As the name suggests, CCM mode combines the well-known counter mode of encryption with the well-known CBC-MAC mode of authentication. The key insight is that the same encryption key can be used for both, provided that the counter values used in the encryption do not collide with the (pre-)initialization vector used in the authentication. A proof of security exists for this combination, based on the security of the underlying block cipher. In fact, the proof also applies to a generalization of CCM for any size block cipher, and in fact, for any size cryptographically strong pseudo-random function (since in both counter mode and CBC-MAC, the block cipher is only ever used in one direction). In cryptography, a block cipher operates on blocks of fixed length, often 64 or 128 bits. ...
In cryptography, an initialization vector (IV) is a block of bits that is combined with the first block of data in any of several modes of a block cipher. ...
In modern cryptography, symmetric key ciphers are generally divided into stream ciphers and block ciphers. ...
CCM mode was designed by Russ Housley, Doug Whiting and Niels Ferguson. At the time CCM mode was developed, Russ Housley was employed by RSA Labratories. RSA Security is a public company NASDAQ: RSAS. Its headquarters are in Bedford, Massachusetts, and it maintains offices in Ireland, the United Kingdom, Singapore, and Japan. ...
Performance CCM requires two block cipher encryption operations per each block of encrypted and authenticated message and one encryption per each block of associated authenticated data.
Patents The catalyst for the development of CCM mode was the submission of OCB mode for inclusion in the IEEE 802.11i standard. Opposition was voiced to the inclusion of OCB mode because of a pending patent application on the algorithm. Inclusion of a patented algorithm meant significant licensing complications for implementors of the standard. OCB mode (Offset Codebook Mode) is a mode of operation for cryptographic block ciphers. ...
IEEE 802. ...
A patent is a set of exclusive rights granted by a state to a person for a fixed period of time in exchange for the regulated, public disclosure of certain details of a device, method, process or composition of matter (substance) (known as an invention) which is new, inventive, and...
Flowcharts are often used to represent algorithms. ...
While the inclusion of OCB mode was disputed based on these intellectual property issues, it was agreed that the simplification provided by an authenticated encryption system was desirable. Therefor Housley, et al. developed CCM mode as a potential alternative that was not encumbered by patents. Intellectual property, or IP, refers to a legal entitlement which sometimes attaches to the expressed form of an idea, or to some other intangible subject matter. ...
Even though CCM mode is less efficient than OCB mode, a patent free solution was preferable to one complicated by patent licensing issues. Therefore, CCM mode went on to become a mandatory component of the IEEE 802.11i standard, and OCB mode was subjugated to the designation of an optional component.
See also External links References - RFC3610: Counter with CBC-MAC (CCM)
- A Critique of CCM
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