Further improvements to the Bauer-Millward attack on the Hill cipher. Issue 5 (2nd September 2016)

• Record Type: Journal Article
• Authors: Leap, Tom; McDevitt, Tim; Novak, Kayla; Siermine, Nicolette
• Is Part Of: Cryptologia. Volume 40:Issue 5(2016)
• Page Start: 452
• Page End: 468
• Publication Date: 2016-09-02
• Subjects: goodness-of-fit -- Hill cipher -- index of coincidence; Cryptography -- Periodicals; 652.8
• DOI: 10.1080/01611194.2015.1087075
• Languages: English
• ISSNs: 0161-1194

Abstract

ABSTRACT: The Bauer-Millward attack on the Hill cipher seeks to recover the individual rows of the decryption matrix instead of the entire matrix. The authors present some improvements to the Bauer-Millward attack that reduce the computational workload by a factor of φ( L ), where φ is the Euler totient function, and L is the length of the alphabet. They also present a method of efficiently combining the top rows to recover the decryption matrix. Performance statistics are provided for blocks up to size 5, and example analyses are given for blocks up to size 8. Previous authors have stopped at size 4.