Cayley–Purser algorithm: Difference between revisions

Revision as of 15:53, 13 November 2006

Revision as of 18:14, 13 November 2006

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Before this placement, Sarah had attended the 1998 [[Young Scientist and Technology Exhibition|ESAT Young Scientist and Technology Exhibition]] with a project describing already existing crytographic techniques from [[Caesar cipher]] to [[RSA]]. This had won her the Intel Student Award which included the opportunity to compete in the 1998 [[Intel International Science and Engineering Fair]] in the United States. Feeling that she needed some original work to add to her exhibition project, Sarah asked Michael Purser for permission to include work based on his cryptographic scheme.

Sarah, onOn advice from her mathematician father, Sarah decided to use [[Matrix (mathematics)|matrices]] to implement Purser's scheme as [[matrix multiplication]] has the necessary property of being non-commutative. As the resulting algorithm would depend on multiplication it would be a great deal faster then the [[RSA]] algorithm which uses an [[exponent|exponential]] step. For her Intel Science Fair project Sarah prepared a demonstration where the same plaintext was enciphered using both RSA and her new Cayley-Purser algorithm and it did indeed show a significant time improvement.

Returning to the ESAT Young Scientist and Technology Exhibition in 1999, Sarah expanded further on the new material she had been working on. She formalised the estimated time the new algorithm would take in comparison to RSA ratherto thanadd merelyto the empirical data from running them against each other. and she hadShe also attempted to determine whether the new algorithm was vulnerable to any attacks which would make it easy to break. To achieve this she had to do a comprehensive surveyinvestigation of possible attacks and had found none which worked.

Sarah did not make any claims that the Cayley-Purser algorithm would definitely replace RSA, knowing that any new cryptographic system would need to stand the test of time before it could be acknowledged as a secure system. The media were not so circumspect however and when she received first prize at the ESAT exhibition, newspapers around the world reported the story that a young girl genius had revolutionised cryptography.