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Block cipher modes

Block ciphers operates on blocks of plain-text and cipher-text. The block size is usually 64 bits. Operating on blocks of 64 bits (8 bytes) is not always useful, and may be vulnerable to simple cryptanalysis attacks. E.g. the same plain-text always produces the same cipher-text, and is especially vulnerable to replay attacks. Several block cipher ``modes of operation'' are in use today. The most common ones are described next.

Asgaut Eng
Wed Apr 10 14:07:30 MET DST 1996