Patent ID: 7320015

Claim:
A method of performing a modulo N exponentiation of a first operand (A) raised to an exponent (E), wherein A, E, and N are each binary numbers of predetermined bit lengths, the method comprising: a) setting a count value (K) to one less than the predetermined bit length of the exponent (E); b) computing a modulo N multiplication of a second operand (B) multiplied by itself (BB mod N); c) computing a modulo N multiplication of the first (A) and the second (B) operands (AB and N) when the K-th bit of the exponent (E) is a one; d) decrementing the count value (K) by one; e) repeating steps b) through d) until the count value (K) equals one; and f) providing to a user, the computed modulo N multiplication of steps (b) and (c) for modulo cryptographic processing.