University of Isfahan & Iranian Society of Cryptology Journal of Computing and Security 2322-4460 3 4 2016 10 01 Multicollision Attack on a recently proposed hash function vMDC-2 211 215 22575 EN Zahra Zolfaghari Shahid Rajaee Teacher Training University Hamid Asadollahi Shahid Rajaee Teacher Training University Nasour Bagheri Shahid Rajaee Teacher Training University Journal Article 2016 12 10 In this paper, we describe an attack on a new double block length hash function which was proposed as a variant of MDC-2 and MDC-4. The vMDC-2 compression function is based on two calls to a block cipher that compresses a 3n-bit string to a 2n-bit one. This attack is based on the Joux's multicollision attack, where we show that an adversary wins finding collision game by requesting $2^{70}$ queries for $ n=128$-bit block cipher that is much less than the complexity of birthday attack. https://jcomsec.ui.ac.ir/article_22575_d9afd4a4e3982aa266b142bb10981c38.pdf