Cryptology ePrint Archive: Report 2010/582

Secret Key Leakage from Public Key Perturbation of DLP-based Cryptosystems

Alexandre Berzati and C\'ecile Canovas-Dumas and Louis Goubin

Abstract: Finding efficient countermeasures for cryptosystems against fault attacks is challenged by a constant discovery of flaws in designs. Even elements, such as public keys, that do not seem critical must be protected. From the attacks against RSA, we develop a new attack of DLP-based cryptosystems, built in addition on a lattice analysis to recover DSA public keys from partially known nonces. Based on a realistic fault model, our attack only requires 16 faulty signatures to recover a 160-bit DSA secret key within a few minutes on a standard PC. These results signi ficantly improves the previous public element fault attack in the context of DLP-based cryptosystems.

Category / Keywords: public-key cryptography / DSA, exponentiation, fault injection, public modulus, lattice reduction.

Date: received 16 Nov 2010

Contact author: cecile dumas at cea fr

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Version: 20101118:033324 (All versions of this report)

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