Fast implementations of RSA cryptography

Abstract

The authors detail and analyze the critical techniques that may be combined in the design of fast hardware for RSA cryptography: chinese remainders, star chains, Hensel's odd division (also known as Montgomery modular reduction), carry-save representation, quotient pipelining, and asynchronous carry completion adders. A fully operational PAM (programmable active memory) implementation of RSA that combines all of the techniques presented here delivers an RSA secret decryption rate over 600-kb/s for 512-b keys, and 165-kb/s for 1-kb keys. This is an order of magnitude faster than any previously reported running implementation. While the implementation makes full use of the PAM's reconfigurability, it is possible to derive from the (multiple PAM designs) implementation a (single) gate-array specification with estimated size under 100 K gates and speed over 1 Mb/s for RSA 512-b keys. Matching gains in software performance which are also analyzed.<>