Thomas Phelippes

One of the secret texts he deciphered

Thomas Phelippes (* 1556 ; † 1625 ) was an English spy and code breaker . He is considered the first British cryptanalyst and, after completing his training as a linguist at Cambridge under the direction of Sir Francis Walsingham, was in the service of Her Majesty Elizabeth I , Queen of England .

Babington plot

He is mainly known for his services in the successful deciphering of the encrypted letters with which the imprisoned Mary I , Queen of Scotland , communicated with the conspirators around John Ballard and Anthony Babington , in July 1586 . The aim of the conspiracy was the liberation of Mary and the murder of the Protestant Queen Elizabeth in order to bring the Catholic Mary to the throne of England. For reasons of confidentiality, the letters were encrypted using a nomenclator , an improved substitution cipher , and smuggled into barrels.

Walsingham had the letters intercepted and handed them to Thomas Phelippes for decipherment. With the help of his linguistic skills and the cryptanalytic method of frequency analysis , he managed to break the ciphertext so that Walsingham could read the content. In this way the plot could be uncovered and the conspirators exposed. This eventually led to the execution of Mary Queen of Scots in February 1587.

literature

Friedrich L. Bauer : Deciphered Secrets. Methods and maxims of cryptology. 3rd, revised and expanded edition. Springer, Berlin et al. 2000, ISBN 3-540-67931-6 .
David Kahn : The Code Breakers - The Story of Secret Writing . Macmillan USA, Reissue 1974, ISBN 0-02-560460-0 .
Simon Singh : Secret Messages . Carl Hanser Verlag, Munich 2000. ISBN 3-446-19873-3 .

Individual evidence

^ Peter Pesic: The Clue to the Labyrinth - Francis Bacon and the Decryption of Nature. Cryptologia . Rose-Hulman Institute of Technology. Taylor & Francis, Philadelphia PA 24.2000,3 (July), p. 198. ISSN 0161-1194 .
^ John F. Dooley: Reviews of Cryptologic Fiction. Cryptologia. Rose-Hulman Institute of Technology. Taylor & Francis, Philadelphia PA 34.2009,1 (January), p. 99. ISSN 0161-1194 .

personal data
SURNAME	Phelippes, Thomas
BRIEF DESCRIPTION	English cryptanalyst
DATE OF BIRTH	1556
DATE OF DEATH	1625

[1] Peter Pesic: The Clue to the Labyrinth - Francis Bacon and the Decryption of Nature. Cryptologia . Rose-Hulman Institute of Technology. Taylor & Francis, Philadelphia PA 24.2000,3 (July), p. 198. ISSN 0161-1194 .

[2] John F. Dooley: Reviews of Cryptologic Fiction. Cryptologia. Rose-Hulman Institute of Technology. Taylor & Francis, Philadelphia PA 34.2009,1 (January), p. 99. ISSN 0161-1194 .