CROSSING Research Seminar: Sponges Resist Leakage: The Case of Authenticated Encryption

10.10.2019, 13:00 – 14:00

10.10.2019 13:00-14:00

Speaker: Patrick Struck, Cryptoplexity, TU Darmstadt | Location: Mornewegstraße 32 (S4|14), Room 5.3.01, Darmstadt

Organizer: CROSSING

In this work we advance the study of leakage-resilient Authenticated Encryption with Associated Data (AEAD) and lay the theoretical groundwork for building such schemes from sponges. Building on the work of Barwell et al. (ASIACRYPT 2017), we reduce the problem of constructing leakage-resilient AEAD schemes to that of building fixed-input-length function families that retain pseudorandomness and unpredictability in the presence of leakage. Notably, neither property is implied by the other in the leakage-resilient setting. We then show that such a function family can be combined with standard primitives, namely a pseudorandom generator and a collision-resistant hash, to yield a nonce-based AEAD scheme. In addition, our construction is quite efficient in that it requires only two calls to this leakage-resilient function per encryption or decryption call. This construction can be instantiated entirely from the T-sponge to yield a concrete AEAD scheme which we call SLAE. We prove this sponge-based instantiation secure in the non-adaptive leakage setting. SLAE bears many similarities and is indeed inspired by ISAP, which was proposed by Dobraunig et al. at FSE 2017. However, while retaining most of the practical advantages of ISAP, SLAE additionally benefits from a formal security treatment.

Short bio
Patrick Struck is a PhD student of Juliane Krämer in the Cryptoplexity group. His research focuses on provable security of cryptographic primitives both against quantum adversaries and side-channel leakage, on which he works within Project P1 of CROSSING.

We will have lunch (pizza) together after the research seminar talk. Please register here: