Spurious transitions in adder circuits: analytical modelling and simulation

International audienceAdder architectures are presented here by an unified formalism, and analysed from the delay, complexity and power consumption points of view. An analytical model for the power consumption is derived, assuming that it is proportional to the transition density. The model is subsequently validated by simulation using a signal transition probabilities propagation tool. Finally, glitches are taken into account when transitions at the input of a cell are separated by one or more cell delays. A redundant to total power ratio is also derived

Conversion from Arithmetic to Boolean Masking with Logarithmic Complexity

A general technique to protect a cryptographic algorithm against side-channel attacks consists in masking all intermediate variables with a random value. For cryptographic algorithms combining Boolean operations with arithmetic operations, one must then perform conversions between Boolean masking and arithmetic masking. At CHES 2001, Goubin described a very elegant algorithm for converting from Boolean masking to arithmetic masking, with only a constant number of operations. Goubin also described an algorithm for converting from arithmetic to Boolean masking, but with O(k) operations where k is the addition bit size. In this paper we describe an improved algorithm with time complexity O(log k) only. Our new algorithm is based on the Kogge-Stone carry look-ahead adder, which computes the carry signal in O(log k) instead of O(k) for the classical ripple carry adder. We also describe an algorithm for performing arithmetic addition modulo 2^k directly on Boolean shares, with the same complexity O(log k) instead of O(k). We prove the security of our new algorithm against first-order attacks. Our algorithm performs well in practice, as for k=64 we obtain a 23% improvement compared to Goubin’s algorithm

Formal Verification of Parallel Prefix Sum

ISSN:0302-9743ISSN:1611-334