Geometric Ideas for Cryptographic Equation Solving in Even Characteristic

  • Authors:
  • Sean Murphy;Maura B. Paterson

  • Affiliations:
  • Information Security Group, Dept. of Mathematics, Royal Holloway, University of London, Egham, U.K. TW20 0EX;Information Security Group, Dept. of Mathematics, Royal Holloway, University of London, Egham, U.K. TW20 0EX

  • Venue:
  • Cryptography and Coding '09 Proceedings of the 12th IMA International Conference on Cryptography and Coding
  • Year:
  • 2009

Quantified Score

Hi-index 0.00

Visualization

Abstract

The GeometricXL algorithm is a geometrically invariant version of the XL algorithm that uses polynomials of a much smaller degree than either a standard Groebner basis algorithm or an XL algorithm for certain multivariate equation systems. However, the GeometricXL algorithm as originally described is not well-suited to fields of even characteristic. This paper discusses adaptations of the GeometricXL algorithm to even characteristic, in which the solution to a multivariate system is found by finding a matrix of low rank in the linear span of a collection of matrices. These adaptations of the GeometricXL algorithm, termed the EGHAM process, also use polynomials of a much smaller degree than a Groebner basis or an XL algorithm for certain equation systems. Furthermore, the paper gives a criterion which generally makes a Groebner basis or standard XL algorithm more efficient in many cryptographic situations.