Faster Modular Exponentiation in JavaScript

Modular exponentiation is the algorithm whose performance determines the performance and practicality of many public key cryptosystems, including RSA, DH and DSA. We have recently achieved a manyfold improvement in the performance of modular exponentiation in JavaScript over the implementation of modular exponentiation in the Stanford JavaScript Crypto Library (SJCL). JavaScript was originally intended for performing simple tasks in web pages, but it has grown into a sophisticated general purpose programming language used for both client and server computing, which is arguably the most important programming language today. Good performance of public key cryptography is difficult to achieve in JavaScript, because JavaScript is an interpreted language inherently slower than a compiled language such as C, and provides floating point arithmetic but no integer arithmetic. But fast JavaScript public key cryptography is worth the effort, because it may radically change the way cryptography is used in web applications. Continue reading “Faster Modular Exponentiation in JavaScript”