My Gadget Just Cares for Me - How NINA Can Prove Security Against Combined Attacks

Abstract

Differential Power Analysis and Differential Fault Analysis threaten the security of even the most trustworthy cryptographic primitives. It is important we protect their implementation such that no sensitive information is leaked using side channels and it withstands injected faults or combined physical attacks. In this work, we propose security notions tailored against advanced physical attacks consisting of both faults and probes on circuit wires. We then transform the security notions to composable security notions. The motivation for this research includes the ease of verification time; the creation of secure components; and the isolation of primitives in larger protocols such as modes of operations. We dub our notion NINA, which forms the link between the established Non-Interference (NI) property and our composable active security property, Non-Accumulation (NA). To illustrate the NINA property, we use it to prove the security of two multiplication gadgets: an error checking duplication gadget and an error correcting duplication gadget. The NINA proofs for error detecting gadgets capture the effect of Statistical Ineffective Fault Analysis (SIFA), an attack vector which threatens most current masked implementations. Additionally, we study error correcting techniques. We show that error correcting gadgets can attain the Independent NINA property. A stronger property which captures a clear separation between the effect of faults and probes. Thus, we show that clever error correcting gadgets improve on error detecting ones by achieving significant higher levels of combined security along with guaranteed output delivery.

Efficient and Private Computations with Code-Based Masking

“…It is an important problem to study how the computations/multiplications can resist to faults. In this respect, we foresee the value of the recent composable secure notions on both side-channel and fault attacks proposed in [DN19], and refer to improvement of the schemes for stronger fault resistance as a prospective further work. Performance improvements with more specific codes.…”

Let’s Tessellate: Tiling for Security Against Advanced Probe and Fault Adversaries

“…The number of probe and faults an adversary needs to place to break the scheme determines the order of security. Definition 1 (Order of Combined Security [11]). A circuit is pd, kqorder combined secure if the following holds against a pd, kq-threshold-probeand-faulting adversary.…”

“…Composable security follows simulation based arguments. For specific definitions and examples, we refer the reader to the following works [3,8,11]. In short, a simulation based proof for a particular gadget works as follows.…”

“…Non-accumulation. The composable security model for active attacks has been considered by Dhooghe and Nikova [11]. This notions demands that a wire fault affects only one output share of the gadget.…”

“…Active adversaries are usually considered as the malicious variant of the probing model where the adversary can choose and fault up to a threshold number of circuit wires. The active (combined) security model is also extended to a composable security model called NINA [11]. Lately more advanced fault attacks such as Dobraunig et al's Statistical Ineffective Fault Attacks (SIFA) [12], which combine Clavier's ineffective faults [9] and Fuhr et al's statistical fault analysis [15], have appeared breaking both side-channel as fault resistant implementations.…”