New Parallel Domain Extenders for UOWHF

We present two new parallel algorithms for extending the domain of a UOWHF. The first algorithm is complete binary tree based construction and has less key length expansion than Sarkar’s construction which is the previously best known complete binary tree based construction. But only disadvantage is that here we need more key length expansion than that of Shoup’s sequential algorithm. But it is not too large as in all practical situations we need just two more masks than Shoup’s. Our second algorithm is based on non-complete l-ary tree and has the same optimal key length expansion as Shoup’s which has the most efficient key length expansion known so far. Using the recent result [9], we can also prove that the key length expansion of this algorithm and Shoup’s sequential algorithm are the minimum possible for any algorithms in a large class of “natural” domain extending algorithms. But its parallelizability performance is less efficient than complete tree based constructi...

• Type: Conference
• Year: 2003
• Where: ASIACRYPT
• Authors: Wonil Lee, Donghoon Chang, Sangjin Lee, Soo Hak Sung, Mridul Nandi
• Keywords: ASIACRYPT 2003, Cryptology, Key Length Expansion, Shoup’s Sequential Algorithm, Tree Based Constructions