Eecient Error-propagating Block Chaining

This document presents EPBC, EEcient Error-Propagating Block Chaining, a new and eecient block encryption mode using both plaintext and ciphertext feedback. This encryption mode is similar to another one, IOBC, and was likewise designed to propagate erroneous decryptions of tampered blocks of ciphered data to all following blocks, hence allowing to validate the integrity of that data using a predeened trailing value. However, EPBC is more secure than IOBC, as it is not vulnerable to any known-plaintext attacks, and is more eecient than IOBC. Performance tests ran on a SPARCstation 10/40 show that EPBC is in average 1.2 times faster than IOBC, and 6.3 to 10.9 times faster than a common combination of an encryption mode and a one-way hash function (CBC and MD5).