METHOD AND DEVICE FOR MODULAR MULTIPLICATION

摘要

The invention relates to a method for modular multiplication of a multiplicand (C) with a multiplicator (M) using a module (N), whereby firstly l multiplication shift values are determined (10), using a multiplication forecast method using l blocks of adjacent multiplicator (M) positions. l Reduction shift values are then determined (13), using a reduction prediction method for the l blocks of multiplicator (M) positions. An intermediate result (Z), from a previous iteration step, the module (N), or a value derived from the module and the multiplicand (C) are processed (16) with the l multiplication shift values and the l reduction shift values to obtain the 2l+1 operands (17). The 2l+1 operands are combined by means of a multi-operand summator (18), to obtain an updated intermediate result (Z') for an iteration step, following the previous iteration step, whereby the iteration is continued until all the multiplicator positions (M) are used. Depending on the number of operands the number of cycles to be calculated may be reduced such that a more rapid calculation of the modular multiplication is possible without an increased hardware complexity.