International Association for Cryptologic Research

International Association
for Cryptologic Research


Srinivas Vivek

Affiliation: IIIT Bangalore


Second-Order Masked Lookup Table Compression Scheme 📺
Annapurna Valiveti Srinivas Vivek
Masking by lookup table randomisation is a well-known technique used to achieve side-channel attack resistance for software implementations, particularly, against DPA attacks. The randomised table technique for first- and second-order security requires about m•2n bits of RAM to store an (n,m)-bit masked S-box lookup table. Table compression helps in reducing the amount of memory required, and this is useful for highly resource-constrained IoT devices. Recently, Vadnala (CT-RSA 2017) proposed a randomised table compression scheme for first- and second-order security in the probing leakage model. This scheme reduces the RAM memory required by about a factor of 2l, where l is a compression parameter. Vivek (Indocrypt 2017) demonstrated an attack against the second-order scheme of Vadnala. Hence achieving table compression at second and higher orders is an open problem.In this work, we propose a second-order secure randomised table compression scheme which works for any (n,m)-bit S-box. Our proposal is a variant of Vadnala’s scheme that is not only secure but also significantly improves the time-memory trade-off. Specifically, we improve the online execution time by a factor of 2n−l. Our proposed scheme is proved 2-SNI secure in the probing leakage model. We have implemented our method for AES-128 on a 32-bit ARM Cortex processor. We are able to reduce the memory required to store a randomised S-box table for second-order AES-128 implementation to 59 bytes.
Generalized Polynomial Decomposition for S-boxes with Application to Side-Channel Countermeasures
Masking is a widespread countermeasure to protect implementations of block-ciphers against side-channel attacks. Several masking schemes have been proposed in the literature that rely on the efficient decomposition of the underlying s-box(es). We propose a generalized decomposition method for s-boxes that encompasses several previously proposed methods while providing new trade-offs. It allows to evaluate $$n\lambda $$ -bit to $$m\lambda $$ -bit s-boxes for any integers $$n,m,\lambda \ge 1$$ by seeing it a sequence of mn-variate polynomials over $$\mathbb {F}_{2^{\lambda }}$$ and by trying to minimize the number of multiplications over $$\mathbb {F}_{2^{\lambda }}$$ .

Program Committees

CHES 2020
CHES 2019
CHES 2018