An Efficient Message Authentication Code Based on Modified MD5-384 Bits Hash Function and Quasigroup

Cryptographic hash functions and HMACs are used to achieve various security goals such as message integrity, message authentication, digital signatures, and entity authentication. This article proposes (1) a new hash function (QGMD5-384) and (2) an efficient message authentication code (QGMAC-384) based on a quasigroup. A quasigroup is a non-associative algebraic structure and its number grows exponentially with its order. Note that the existing hash functions and HMACs that use quasigroups are vulnerable to prefix and suffix attacks. The security of the proposed hash function is analyzed by comparing it with the MD5 and SHA-384. It is found that the proposed QGMD5-384 is more secure. Also, QGMAC-384 is analyzed against brute force and forgery attacks and it is found to be resistant to these attacks. The performance of the new schemes is compared with their counterparts, such as SHA-384 and HMAC-SHA-384. It is observed that QGMD5-384 and QGMAC-384 are slightly slower than MD5 and HMAC-MD5, respectively, but faster than both the SHA-384 and the HMAC-SHA-384.