Optimized implementation of RSA cryptosystem

Modular exponentiation is being used more and more in security mechanisms such as encipherment schemes, authentication, digital signatures etc. In this paper some modular exponentiation algorithms with an original optimization method are described. These algorithms have been used to implement a software version of the RSA asymmetric cipher on several general-purpose machines. The performance is 50% faster than the best-known algorithms on the same machines. In many applications that need relatively slow decipherment throughput, software-implemented algorithms are therefore an acceptable alternative to specialized hardware.