Unbridle the bit-length of a crypto-coprocessor with montgomery multiplication

  • Authors:
  • Masayuki Yoshino;Katsuyuki Okeya;Camille Vuillaume

  • Affiliations:
  • Hitachi, Ltd., Systems Development Laboratory, Kawasaki, Japan;Hitachi, Ltd., Systems Development Laboratory, Kawasaki, Japan;Hitachi, Ltd., Systems Development Laboratory, Kawasaki, Japan

  • Venue:
  • SAC'06 Proceedings of the 13th international conference on Selected areas in cryptography
  • Year:
  • 2006

Quantified Score

Hi-index 0.00

Visualization

Abstract

We present a novel approach for computing 2n-bit Montgomery multiplications with n-bit hardware Montgomery multipliers. Smartcards are usually equipped with such hardware Montgomery multipliers; however, due to progresses in factoring algorithms, the recommended bit length of public-key schemes such as RSA is steadily increasing, making the hardware quickly obsolete. Thanks to our doublesize technique, one can re-use the existing hardware while keeping pace with the latest security requirements. Unlike the other double-size techniques which rely on classical n-bit modular multipliers, our idea is tailored to take advantage of n-bit Montgomery multipliers. Thus, our technique increases the perenniality of existing products without compromises in terms of security.