OCB Mode 11

Collision attacks on OCB

We show that collision attacks are quite effective on the OCB block cipher mode. When a collision occurs OCB loses its authentication capability. To keep adequate authentication security OCB has to be limited in the amount of data it processes. This restriction is relevant to real-life applications, and casts doubt on the wisdom of using OCB.

The Software Performance of Authenticated-Encryption Modes

We study the software performance of authenticated-encryption modes CCM, GCM, and OCB. Across a variety of platforms, we find OCB to be substantially faster than either alternative. For example, on an Intel i5 (“Clarkdale”) processor, good implementations of CCM, GCM, and OCB encrypt at around 4.2 cpb, 3.7 cpb, and 1.5 cpb, while CTR mode requires about 1.3 cpb. Still we find room for algorithm...

Software Implementation of OCB Mode

The OCB (Offset Code Book) is a block cipher mode of operation used for encryption which provides both confidentiality and authenticity at the same time. This implementation is cost efficient as we do not have to design a separate hardware for authentication process. The OCB can be executed on any platform like C, JAVA and Assembly languages. This implies that it can be implemented by hardware ...

OCB Mode

A Brief Overview of the OCB Mode of Operation for Block Ciphers Cryptology project by