Contra-medida por randomização de acesso à memória em arquitetura de criptografia de chave pública

Abstract

The expansion of the data communication, due to the large ow of information that pass through these systems has meant that the security becomes an item of constant concern. Even when considering the efficient encryption systems that exists today, which present relevant mathematical protection, some implementations in hardware of these systems will favor the leak of confidential information through side channels attacks, such as power consumption and electromagnetic radiation. Performance issues have fundamental importance in the design of a physical system, however aspects which make the system robust against side channel attacks has gotten more attention nowadays.This work focuses on hardware architectures based on the RSA public key algorithm, proposed by Rivest, Shamir and Adleman in 1977, which presents the modular exponentiation operation, calculated from several modular multiplications, as main operation. The RSA algorithm involves integers in order of 1024 or 2048 bits, so the division inherent in modular multiplications can become a major problem. In order to avoid these divisions, the Montgomery algorithm, proposed in 1985, appears as an efficient alternative. On this context, this dissertation presents a multiplexed architecture based on the properties of the Montgomery's algorithm. Forwarding, an improvement to this architecture is presented, implemented with the randomization of internal memories accesses, in order to increase system robustness against specialized side-channel attacks. Thus, the implemented architecture is exposed to side channels SPA (Simple Power Analysis) and SEMA (Simple Electromagnetig Analysis) and the aspects of security and robustness of the implemented system are evaluated and presented.