U.S. Philips Corporation

Irdeto Corporate B.v.

Hendrik D L Hollmann

Marten Erik Van Dijk

Petrus Johannes Lenoir

Ludovicus M G M Tolhuizen

Paulus M H M A Gorissen

Wilhelmus P A J Michiels

A method of creating an encryption system for encrypting a plurality of plaintext words is provided. The method comprises associating () respective plaintext words () with respective sets () of error positions () of an error vector, and associating () respective values of at least one of the plaintext words () with respective error vector values, wherein positions of the respective error vector values outside the set () of error positions associated with the one of the plaintext words () are zero. The method further comprises associating () the respective values of the plaintext word () with respective representations of respective syndromes () of the respective error vectors according to an error correcting code.

Cryptographic system

An encrypting exponentiation modulo M is effected by a modular multiplication X*YmodM, where M is a temporally steady but instance-wise non-uniform modulus. The method involves an iterative series of steps. Each step executes one or two first multiplications to produce a first result, and a trim-down reduction of the size of the first result by one or more second multiplications to produce a second result. The method furthermore takes a distinctive measure for keeping the final result of each step below a predetermined multiplicity of the modulus. In particular, the method postpones substantially any subtraction of the modulus as pertaining to the measure to a terminal phase of the modular exponentiation. This is possible through choosing in an appropriate manner one or more parameters figuring in the method. This further maintains overall temporal performance.

Method and device for executing a decrypting mechanism through calculating a standardized modular exponentiation for thwarting timing attacks

Growing community of inventors

Eindhoven, Netherlands

Hendrik D L Hollmann