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Sean Murphy

success fail Jun JAN Feb 31 2008 2009 2010 150 captures 03 Jun 2002 - 29 Sep 2018 About this capture COLLECTED BY Organization: Alexa Crawls Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period. Collection: alexa_web_2009 this data is currently not publicly accessible. TIMESTAMPS Sean Murphy

I am a Professor in the Department of Mathematics at Royal Holloway (University of London), working in cryptology.

The Department runs an M.Sc. in Information Security with about 120 students (also available as a distance learning M.Sc.). The Mathematics Department also runs B.Sc. and M.Sc. programmes in Mathematics. There are about 60 Ph.D. students in the Department.


My academic research concentrates on symmetric cryptography. I was involved with the NESSIE project, a European project to assess cryptographic primitives for future possible standardisation. I also helped set up ECRYPT project, a European Network of Excellence in Cryptology. Much of recent work has centred on the (National Institute of Standards and Technology) Advanced Encryption Standard (AES), and I was Principal Investigator of the Engineering and Physical Sciences Research Council (EPSRC) project Security Analysis of the Advanced Encryption Standard. I am also interested the use of stochastic and statistical techniques in cryptology. Some of my publications are listed below.


  • Carlos Cid, Sean Murphy and Matthew Robshaw, Algebraic Apsects of the Advanced Encryption Standard, Springer, ISBN 0-387-24363-1, August 2006.

  • Fred Piper and Sean Murphy, Cryptography: a Very Short Introduction, Oxford University Press, ISBN 0-19-280315-8, 2002.

    Advanced Encryption Standard (AES)

  • S. Murphy and M.B. Paterson `A Geometric View of Cryptographic Equation Solving', Journal of Mathematical Cryptology, Vol. 2, pages 63-107, 2008. A version is available as Departmental Technical Report RHUL-MA-2007-4. This is a paper not directly about the AES, but is part of the EPSRC AES project.

  • Wen-Ai Jackson and S. Murphy, `Projective Aspects of the AES Inversion', Designs, Codes and Cryptography, Vol. 43, pages 167-179, 2007. A version is available as Departmental Technical Report RHUL-MA-2006-4.

  • C.Cid, S.Murphy and M.Robshaw, 'An Algebraic Framework for Cipher Embeddings', Proceedings of the 10th IMA International Conference on Coding and Cryptography, LNCS 3796, pages 278-289, 2005.

  • C.Cid, S.Murphy and M.Robshaw, Small Scale Variants of the AES , Fast Software Encryption - FSE2005, LNCS 3557, pages 145-162, 2005.

  • C.Cid, S.Murphy and M.Robshaw, `Computational and Algebraic Aspects of the Advanced Encryption Standard', Seventh International Workshop on Computer Algebra in Scientific Computing, CASC 2004, pp. 93-103, St. Petersburg, Russia, 2004.

  • S.Murphy and M.Robshaw, `Comments on the Security of the AES and the XSL Technique', Electronic Letters, Vol. 39, pages 36-38, 2003.

  • S.Murphy and M.Robshaw, `Essential Algebraic Structure within the AES', Advances in Cryptology -- CRYPTO 2002, Lecture Notes in Computer Science 2442, M. Yung (Ed.) (Springer, Berlin, 2002), pp. 1-16. Errata and the matrices M and M* are available.

  • S.Murphy and M.Robshaw. `New Observations on Rijndael', AES Comment to NIST, August 2000. This is a note on the linear diffusion layer in Rijndael. The designers' response: `Answer to New Observations on Rijndael', AES Comment to NIST, August 2000. A further note concerning the linear diffusion layer of Rijndael: `Further Comments on the Structure of Rijndael', AES Comment to NIST, August 2000.

    Stochastic and Statistical Issues in Cryptology

  • S.Murphy, `The Independence of Linear Approximations in Symmetric Cryptology', IEEE Transactions on Information Theory, Vol. 52, pp5510-5518, 2006.

  • S.Murphy and M.Robshaw, `Differential Cryptanalysis, Key-Dependent S-Boxes and Twofish', Designs, Codes and Cryptography, Vol. 27, pp229-255, 2002.

  • S.Murphy, `The Power of NIST's Statistical Testing of AES Candidates', AES Comment to NIST, April 2000.

  • D. Erdmann and S. Murphy, `An Approximate Distribution for the Maximum Order Complexity' Designs, Codes and Cryptography, Vol. 10, pp. 325-329, 1997.

  • S. Murphy, F.Piper, M.Walker and P.Wild, `Maximum Likelihood Estimation for Block Cipher Keys' Research Report 1995 (Similar versions 1992 and 1994). Available as Departmental Technical Report RHUL-MA-2006-3.

  • D. Davies and S. Murphy, `Pairs and Triplets of DES S-Boxes' J. Cryptology, Vol. 8, pp. 1-25, 1995.

  • X. Lai, J. Massey and S. Murphy, `Markov Ciphers and Differential Cryptanalysis' in Advances in Cryptology -- EUROCRYPT `91 , LNCS 547,, pp. 17-38, 1991.

    NESSIE Reports

  • The NESSIE project was an EU project (2000-03) to assess cryptographic algorithms for possible standardisation.

  • B.Breneel et al, `The NESSIE Book', April 2004.

  • B.Breneel et al, `NESSIE Security Report', April 2003.

  • S.Murphy and J.White (editors), `Security Evaluation of NESSIE First Phase', September 2001.

  • S.Murphy (Editor), `Comments by the NESSIE Project on the AES Finalists', AES Comment to NIST, May 2000.

    Other Cryptology Publications

  • S.Murphy, `The Key Separation of Twofish', AES Comment to NIST, April 2000.

  • F.Mirza and S. Murphy, `An Observation on the Key Schedule of Twofish', NIST 2nd AES Conference, Rome, Italy, March 1999.

  • S. Murphy, `An Analysis of SAFER', J. Cryptology. Vol. 11, pp235--251, 1998.

  • S.R.Blackburn, K. Brincat, F. Mirza and S. Murphy, `Cryptanalysis of ``Labyrinth'' stream cipher', Electronics Letters, Vol. 34, pp. 1220-1221, 1998.

  • S. Murphy, `Comment on "Bound for linear complexity of BBS sequences" ' Electronics Letters, Vol. 34, pp. 1057-1058, 1998.

  • S.R.Blackburn, S. Murphy and K.G. Paterson, `A Comment on ``A New Public-Key Cipher System Based Upon Diophantine Equations'' ', IEEE Trans. Comp., Vol. 46, pp. 512, 1997.

  • S.R.Blackburn, S. Murphy and K.G. Paterson, `Comments on ``Theory and Applications of Cellular Automata to Cryptography'' ', IEEE Trans. Comp., Vol. 46, pp. 637-638, 1997.

  • S.R.Blackburn, G. Carter, D. Gollmann, S. Murphy, K.Paterson, F.Piper, and P. Wild, `Aspects of Linear Complexity', in Communications and Cryptography, (Blahut, Costello, Maurer, Mittelholzer eds) pp. 35-42, Kluwer, 1994.

  • S.R.Blackburn, S. Murphy and J. Stern, `The Cryptanalysis of a Public Key Implementation of Finite Group Mappings' J. Cryptology, Vol. 8, pp. 157-166, 1995.

  • S. Murphy, K.Paterson and P. Wild, `A Weak Cipher that generates the Symmetric Group' J. Cryptology, Vol. 7, pp. 61-65, 1994.

  • S.R.Blackburn, S. Murphy and J. Stern, `Weaknesses of a Public-Key Cryptosy stem based on Factorizations of Finite Groups' in Advances in Cryptology -- EUROCRYPT `93, LNCS 765, pp. 50-54, 1994.

  • S. Murphy, `Remarks on the LUC public key system' Electronics Letters, Vol. 30, pp. 558-559, 1992.

  • D. Erdmann and S. Murphy, `The Henon Stream Cipher' Electronics Letters, Vol. 28, pp. 893-895, 1992.

  • S. Murphy, `The Cryptanalysis of FEAL-4 using 20 chosen plaintexts' J. Cryptology, Vol. 2, pp. 145-154, 1990.
    Note that the copyright of most of these publications belongs to the relevant publisher.

    Sean Murphy

    Professor Sean Murphy,
    Department of Mathematics,
    Royal Holloway, University of London,
    Egham, Surrey TW20 0EX, U.K.
    Phone: +44 (0)1784 443699
    Fax : +44 (0)1784 430766
    Email: [email protected]