Towards an FPGA Architecture Optimized for Public-Key Algorithms

A. Elbirt, Chris­tof Paar

The SPIE's Symposium on Voice, Video, and Data Communications, Boston, MA. September 19-22, 1999.


Cryptographic algorithms are constantly evolving to meet security needs, and modular arithmetic is an integral part of these algorithms, especially in the case of public-key cryptosystems. To achieve optimal system performance while maintaining physical security, it is desirable to implement cryptographic algorithms in hardware. However, many public-key cryptographic algorithms require the implementation of modular arithmetic, specifically modular multiplication, for operands of 1024 bits in length. Additionally, algorithm agility is required to support algorithm independent protocols, a feature of most modern security protocols. Reprogrammability, particularly in-system reprogrammability, is critical in enabling the switching between cryptographic algorithms required for algorithm independent protocols. Field Programmable Gate Arrays (FPGAs) are a viable option for achieving this goal. Ideally, the targeted FPGA will have been designed with the architectural requirements for wide-operand modular arithmetic in mind in an effort to maximize system performance. This contribution investigates existing FPGA architectures with respect to modular multiplication. It also proposes a new FPGA architecture optimized for the wide-operand additions required for modular multiplication.


tags: FPGA, modular arithmeti, Montgomery Reduction, public-key cryptography