Fast Squaring Algorithm Design and Complexity Numerical Analyses for Public-Key Cryptosystems

Modular exponentiation is an important operation in several public-key cryptography. The standard squaring algorithm is well-known and the Guajardo-Paar algorithm fixes the improper carry handling bug produced by the standard squaring algorithm, but produces error-indexing bug. In this paper, one squaring algorithm is proposed, which stores base products into the Look-Up Table before the squaring computation and base size comparison method. The proposed algorithm can not only evaluate squaring efficiently but also avoid bugs produced in other proposed algorithms (the Guajardo-Paar algorithm and the Yang-Heih-Laih algorithm). The performance of the proposed algorithm is 1.615 times faster than the standard squaring algorithm and much faster than others’ algorithms.