Fast Encryption and Authentication: XCBC Encryption and XECB Authentication Modes
Virgil D. Gligor5
and Pompiliu Donescu5 
| (5) |
VDG Inc., 6009 Brookside Drive, Chevy Chase, MD, 20815 |
Abstract
We present the eXtended Ciphertext Block Chaining (XCBC) and the eXtended Electronic Codebook (XECB) encryption schemes or
modes of encryption that can detect encrypted-message forgeries with high probability even when used with typical non-cryptographic
Manipulation Detection Code (MDC) functions (e.g., bitwise exclusive-or and cyclic redundancy code (CRC) functions). These
modes detect encrypted-message forgeries at low cost in performance, power, and implementation, and preserve both message
secrecy and integrity in a single pass over the message data. Their performance and security scale directly with those of
the underlying block cipher function. We also present the XECB message authentication (XECB-MAC) modes that have all the operational
properties of the XOR-MAC modes (e.g., fully parallel and pipelined operation, incremental updates, and out-of-order verification),
and have better performance. They are intended for use either stand-alone or with encryption modes that have similar properties
(e.g., counter-based XOR encryption). However, the XECB-MAC modes have higher upper bounds on the probability of adversary’s
success in producing a forgery than the XOR-MAC modes.
This work was performed while this author was on sabbatical leave from the University of Maryland, Department of Electrical
and Computer Engineering, College Park, Maryland 20742.
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