Design Methodology for Throughput Optimum Architectures of Hash Algorithms of the MD4-class

Abstract

Abstract. In this paper we propose an architecture design methodology to optimize the throughput of MD4-based hash algorithms. The proposed methodology includes an iteration bound analysis of hash algorithms, which is the theoretical delay limit, and DFG (Data Flow Graph) transformations to achieve the iteration bound. We applied the methodology to some MD4-based hash algorithms such as SHA1, MD5 and RIPEMD-160. Since SHA1 is the algorithm which requires all the techniques we show, we also synthesized the transformed SHA1 algorithm in a 0.18µm CMOS technology in order to verify its correctness and its achievement of high throughput. To the best of our knowledge, the proposed SHA1 architecture is the first to achieve the theoretical throughput optimum beating all previously published results. Though we demonstrate a limited number of examples, this design methodology can be applied to any other MD4-based hash algorithm.

Unfolding Method for Shabal on Virtex-5 FPGAs: Concrete Results

“…But with 6 and 8, the TP decreases, showing up the limit of the unfolding method due to operations added and more complex place-route step. We hope that this effect can be reduced with retiming method described in [9].…”

“…In order to improve performance, we perform an unfolding transformation [9] on P. This technique is often used in designs which have a NLFSR structure, such as some stream ciphers like Grain and Trivium; it is also interesting to measure its efficiency on Shabal, since one iteration in P is viewed as a NLFSR (see Fig. 2).…”

“…This can be viewed as an unfolding transformation of "factor" 1. The requirement on this "unfolding factor" is to be a denominator of the iteration bound [9]; in Shabal permutation case: 48.…”

“…Other divisors of 48 are also possible values for f (12,16,24), but applying only unfolding method, they do not bring any improvement on the throughput. For these great factors, it will be necessary to apply retiming methods [9]. 1) Unfolding 2 iterations in P: So the unfolding method transforms the NLFSR.…”

“…In this paper, we present optimizations for designing highly efficient implementations of Shabal, using intensive unfolding transformation described for example in [7], [8], [9]. This method leads to unroll the Shabal core.…”