On the Memory-Hardness of Data-Independent Password-Hashing Functions
Joël Alwen, Peter Gaži, Chethan Kamath, Karen Klein, Georg Osang, Krzysztof Pietrzak, Lenoid Reyzin, Michal Rolínek, Michal Rybár · 2018
We show attacks on five data-independent memory-hard functions (iMHF) that were submitted to the password hashing competition (PHC). Informally, an MHF is a function which cannot be evaluated on dedicated hardware, like ASICs, at significantly lower hardware and/or energy cost than evaluating a single instance on a standard single-core architecture. Data-independent means the memory access pattern of the function is independent of the input; this makes iMHFs harder to construct than data-dependent ones, but the latter can be attacked by various side-channel attacks.