JHAE: A Novel Permutation-Based Authenticated Encryption Mode Based on the Hash Mode JH

In this paper JHAE, an authenticated encryption (AE) mode, was presented based on the JH hash mode. JHAE is an on-line and single-pass dedicated AE mode based on permutation that supports optional associated data (AD). It was proved that this mode, based on ideal permutation, achieved privacy and integrity up to O(2n=2) queries where the length of the used permutation was 2n. To decrypt, JHAE did not require the inverse of its underlying permutation and therefore saved area space. JHAE has been used by Artemia, one of the CAESAR candidates

Message-locked Encryption with File Update

Message-locked encryption (MLE) (formalized by Bellare, Keelveedhi and Ristenpart, 2013) is an important cryptographic primitive that supports deduplication in the cloud. Updatable block-level message-locked encryption (UMLE) (formalized by Zhao and Chow, 2017) adds the update functionality to the MLE. In this paper, we formalize and extensively study a new cryptographic primitive file-updatable message-locked encryption (FMLE). FMLE can be viewed as a generalization of the UMLE, in the sense that unlike the latter, the former does not require the existence of BL-MLE (block-level message-locked encryption). FMLE allows more flexibility and efficient methods for updating the ciphertext and tag. Our second contribution is the design of two efficient FMLE constructions, namely, RevD-1 and RevD-2, whose design principles are inspired from the very unique reverse decryption functionality of the FP hash function (designed by Paul, Homsirikamol and Gaj, 2012) and the APE authenticated encryption (designed by Andreeva et al., 2014). With respect to UMLE – which provides so far the most efficient update function – RevD-1 and RevD-2 reduce the total update time by at least 50%, on average. Additionally, our constructions are storage efficient. We also give extensive comparison between our and the existing constructions

A Novel Permutation-based Hash Mode of Operation FP and The Hash Function SAMOSA

The contribution of the paper is two-fold. First, we design a novel permutationbased hash mode of operation FP, and analyze its security. The FP mode is derived by replacing the hard-to-invert primitive of the FWP mode – designed by Nandi and Paul, and presented at Indocrypt 2010 – with an easy-to-invert permutation; since easy-to-invert permutations with good cryptographic properties are normally easier to design, and are more efficient than the hard-to-invert functions, the FP mode is more suitable in practical applications than the FWP mode. We show that any n-bit hash function that uses the FP mode is indifferentiable from a random oracle up to 2n/2 queries (up to a constant factor), if the underlying 2n-bit permutation is free from any structural weaknesses. Based on our further analysis and experiments, we conjecture that the FP mode is resistant to all non-trivial generic attacks with work less than the brute force, mainly due to its large internal state. We compare the FP mode with other permutation-based hash modes, and observe that it displays the so far best security/rate trade-off. To put this into perspective, our second contribution is a proposal for a concrete hash function SAMOSA using the new mode and the P-permutations of the SHA-3 finalist Grøstl. Based on our analysis we claim that the SAMOSA family cannot be attacked with work significantly less than the brute force. We also provide hardware implementation (FPGA) results for SAMOSA to compare it with the SHA-3 finalists. In our implementations, SAMOSA family consistently beats Grøstl, Blake and Skein in the throughput to area ratio. With more efficient underlying permutation, it seems possible to design a hash function based on the FP mode that can achieve even higher performances

A Novel Permutation-based Hash Mode of Operation FP and the Hash Function SAMOSA

status: publishe