On the Efficiency of Fast RSA Variants in Modern Mobile Phones

Modern mobile phones are increasingly being used for more services that require modern security mechanisms such as the public-key cryptosystem RSA. It is, however, well-known that public-key cryptography demands considerable computing resources and that RSA encryption is much faster than RSA decryption. It is consequently an interesting question if RSA as a whole can be executed efficiently on modern mobile phones. In this paper, the authors explore the efficiency on modern mobile phones of variants of the RSA cryptosystem, covering CRT, Multi-Prime RSA, Multi-Power RSA, Rebalanced RSA and R-Prime RSA by comparing the encryption and decryption time using a simple Java implementation and a typical RSA setup.