Practical leakage-resilient pseudorandom objects with minimum public randomness

One of the main challenges in leakage-resilient cryptography is to obtain proofs of security against side-channel attacks, under realistic assumptions and for efficient constructions. In a recent work from CHES 2012, Faust et al. proposed new designs of stream ciphers and pseudorandom functions for this purpose. Yet, a remaining limitation of these constructions is that they require large amounts of public randomness to be proven leakage-resilient. In this paper, we show that tweaked designs with minimum randomness requirements can be proven leakage-resilient in minicrypt. That is, either these constructions are secure, or we are able to construct public-key cryptographic primitives from symmetric-key building blocks and their leakage functions (which is very unlikely). Hence, our results improve the practical relevance of two important leakage-resilient pseudorandom objects.