1 a Faculty of Communication and Information Technology, Imam Hossein University (IHU), Iran

2 Iran University of Science and Technology (IUST), Iran

3 Shahid Bahonar University of Kerman, Kerman, Iran


Critical overlap situations in the classical Hellman's cryptanalytic time memory trade-off method can be avoided, provided that during the precomputation phase, we generate perfect chains which are merge-free and loop-free chains. In this paper, we present asymptotic behavior of perfect chains in terms of time memory trade-off attacks. More precisely, we obtained expected values and variances for the coverage of perfect chains. We have also confirmed our theoretic outcomes with test results.