Patent ID: 6745220
Filing Date: 2004-06-01
Classification: G06F

Abstract:
A computer implemented method for calculating an encrypted value representing a data string raised to a power represented by a binary exponent value, the method comprising the steps of:applying a signed digit algorithm to the binary exponent value to generate a processed exponent value; constructing a look-up table of substrings that are likely to be encountered in the processed exponent value each entry in the look-up table corresponding to the data string raised to the power represented by the respective substring; applying a string replacement method to traverse the processed exponent value and retrieving, from the lookup table, and recording, intermediate values corresponding to matching substrings in the processed exponent value and replacing the matching substrings in the processed exponent value by zeros and a reference to the look-up table to produce a modified recoded string representation of the exponent value; and applying a multiply-square chain algorithm to the recoded exponent value using the look-up table to calculate the encrypted value representing the data string raised to the recoded exponent value.