On Modes of Operations of a Block Cipher for Authentication and Authenticated Encryption

This work deals with the various requirements of encryption and authentication in cryptographic applications. The approach is to construct suitable modes of operations of a block cipher to achieve the relevant goals. A variety of schemes suitable for specific applications are presented. While none of the schemes are built completely from scratch, there is a common unifying framework which connects them. All the schemes described have been implemented and the implementation details are publicly available. Performance figures are presented when the block cipher is the AES and the Intel AES-NI instructions are used. These figures suggest that the constructions presented here compare well with previous works such as the famous OCB mode of operation. In terms of features, the constructions provide several new offerings which are not present in earlier works. This work significantly widens the range of choices of an actual designer of cryptographic system