Giovan Battista Bellaso

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Such “scrambled” alphabets were proposed by Bellaso in 1553. The key letters can be seen in the leftmost column.
A 1555 revised version by Bellaso, again with involutor (self-inverse) alphabets

Giovan Battista Bellaso (* 1505 in Brescia , † between 1568 and 1581 probably in Rome ) was an Italian cryptologist .

Life

Little is known about his life and some of the information received is contradictory. He grew up in a respected family, the son of a patrician named Piervincenzo from Brescia, one of the wealthiest cities in Lombardy in the early 16th century , and later moved to Padua . According to records in the archives of the University of Padua , he spent the years 1537–38 there and graduated in law in 1538 . The year of his death is unknown, but it is believed to be between 1568 and 1581. He probably died in Rome .

Cryptology

Bellaso dealt with cryptology , as many were doing at the time, including for the Roman Curia . From his French contemporary Blaise de Vigenère (1523–1596) it is recorded that Bellaso improved the then new polyalphabetic substitution by suggesting the use of a key . In the form originally proposed by the German Benedictine abbot Johannes Trithemius (1462–1516) in 1508, simply one alphabet after the other should be used to encode a tabula recta ( Latin for "square table") . Bellaso suggested that instead of this fixed procedure, the alphabets should be chosen irregularly in the form of a password or a passphrase that could be freely chosen by the encryptor . He also used the "scrambled" alphabets proposed as early as 1466 by his compatriot Leon Battista Alberti (1404–1472) , whereby he restricted himself to involutorial ones. So he invented polyalphabetic encryption with a password.

Although many users then liked to use easy-to-remember, but also easy-to-guess and thus cryptographically weak passwords or passphrases, such as VIRTVTI OMNIA PARENT (“Everything obeys efficiency”) , Bellaso's proposal represented a considerable cryptographic strengthening of the method. The letters of the label determine the order in which the various alphabets are selected from the table . This resulted in the Vigenère cipher , which in the centuries to come was also known as le chiffre indéchiffrable ( French for "the indecipherable cipher").

Fonts

Foreword to his third book (1564)
  • La cifra del Sig. Giovan Battista Bel [l] aso, gentil'huomo bresciano, nuovamente da lui medesimo ridotta a grandissima brevita et perfettione. Venice, 1533.
  • Novi et singolari modi di cifrare de l'eccellente dottore di legge knife Giouan Battista Bellaso nobile bresciano. Brescia, Lodovico Britannico, 1555.
  • Il vero modo di scrivere in cifra con facilita, prestezza, et securezza di Misser Giovan Battista Bellaso, gentil'huomo bresciano. Bressa, Iacobo Britannico, 1564.

literature

Web links

Individual evidence

  1. ↑ Augusto Buonafalce: Bellaso's Reciprocal Ciphers . Cryptologia, 30: 1, p. 39, 2006, doi: 10.1080 / 01611190500383581
  2. ↑ Encryption according to Bellaso.Retrieved : May 30, 2016.
  3. ↑ Augusto Buonafalce: Bellaso's Reciprocal Ciphers . Cryptologia, 30: 1, p. 40, 2006, doi: 10.1080 / 01611190500383581
  4. ↑ Friedrich L. Bauer: Deciphered secrets - methods and maxims of cryptology . Springer, Berlin 2000 (3rd edition), ISBN 3-540-67931-6 , pp. 134-136.
  5. ↑ Augusto Buonafalce: Bellaso's Reciprocal Ciphers . Cryptologia, 30: 1, p. 39, 2006, doi: 10.1080 / 01611190500383581
  6. ↑ Augusto Buonafalce: Bellaso's Reciprocal Ciphers . Cryptologia, 30: 1, p. 39, 2006, doi: 10.1080 / 01611190500383581
  7. ↑ Augusto Buonafalce: Bellaso's Reciprocal Ciphers . Cryptologia, 30: 1, p. 40, 2006, doi: 10.1080 / 01611190500383581
  8. ↑ Friedrich L. Bauer: Deciphered secrets. Methods and maxims of cryptology. 3rd, revised and expanded edition. Springer, Berlin et al. 2000, p. 139.
  9. ↑ Augusto Buonafalce: Bellaso's Reciprocal Ciphers . Cryptologia, 30: 1, p. 41, 2006, doi: 10.1080 / 01611190500383581
  10. ↑ Tobias Schrödel: Breaking Short Vigenère Ciphers , Cryptologia, 32: 4, 2008, pp. 334–347, doi: 10.1080 / 01611190802336097 (English). Retrieved May 30, 2016.
personal data
SURNAME Bellaso, Giovan Battista
BRIEF DESCRIPTION Italian cryptologist
DATE OF BIRTH 1505
PLACE OF BIRTH Brescia
DATE OF DEATH between 1568 and 1581
Place of death uncertain: Rome