Editing Kerckhoffs's principle (section)

==Origins==
The invention of [[telegraphy]] radically changed [[military communications]] and increased the number of messages that needed to be protected from the enemy dramatically, leading to the development of field ciphers which had to be easy to use without large confidential [[codebook]]s prone to capture on the battlefield.<ref>{{Cite web |title=[3.0] The Rise Of Field Ciphers |url=https://vc.airvectors.net/ttcode_03.html |access-date=2024-01-11 |website=vc.airvectors.net |archive-date=2024-01-11 |archive-url=https://web.archive.org/web/20240111165128/https://vc.airvectors.net/ttcode_03.html |url-status=live }}</ref> It was this environment which led to the development of Kerckhoffs's requirements.

Auguste Kerckhoffs was a professor of German language at [[HEC Paris|Ecole des Hautes Etudes Commerciales]] (HEC) in Paris.<ref>{{cite web |title=August Kerckhoffs: the father of computer security - History |url=https://china.exed.hec.edu/en/node/467 |website=china.exed.hec.edu |publisher=[[HEC Paris]] |access-date=26 November 2022 |language=en |archive-date=26 November 2022 |archive-url=https://web.archive.org/web/20221126024206/https://china.exed.hec.edu/en/node/467 |url-status=live }}</ref> In early 1883, Kerckhoffs's article, ''La Cryptographie Militaire'',<ref>{{citation | url = http://petitcolas.net/fabien/kerckhoffs/ | title = Electronic version and English translation of "La cryptographie militaire" | first = Fabien | last = Petitcolas | access-date = 2004-06-29 | archive-date = 2015-10-10 | archive-url = https://archive.today/20151010133258/http://www.petitcolas.net/kerckhoffs/index.html | url-status = live }}</ref> was published in two parts in the ''Journal of Military Science'', in which he stated six design rules for military [[cipher]]s.{{hsp}}<ref name="Kahn">{{citation | first = David | last = Kahn | title = The Codebreakers: the story of secret writing | year = 1996|edition=Second | publisher = Scribners}} p.235</ref> Translated from French, they are:<ref>{{cite journal |first=Auguste |last=Kerckhoffs |url=https://www.petitcolas.net/kerckhoffs/crypto_militaire_1_b.pdf |title=La cryptographie militaire |trans-title=Military cryptography |journal=Journal des sciences militaires |trans-journal=Military Science Journal |volume=IX |pages=5–83 |date=January 1883 |language=fr |access-date=2019-12-17 |archive-date=2021-02-20 |archive-url=https://web.archive.org/web/20210220151435/https://www.petitcolas.net/kerckhoffs/crypto_militaire_1_b.pdf |url-status=live }}</ref><ref>{{cite journal |first=Auguste |last=Kerckhoffs |url=https://www.petitcolas.net/kerckhoffs/crypto_militaire_2.pdf |title=La cryptographie militaire |trans-title=Military cryptography |journal=Journal des sciences militaires |trans-journal=Military Science Journal |volume=IX |pages=161–191 |date=February 1883 |language=fr |access-date=2019-12-17 |archive-date=2021-02-20 |archive-url=https://web.archive.org/web/20210220151434/https://www.petitcolas.net/kerckhoffs/crypto_militaire_2.pdf |url-status=live }}</ref>

# The system must be practically, if not mathematically, indecipherable;
# It should not require secrecy, and it should not be a problem if it falls into enemy hands;
# It must be possible to communicate and remember the key without using written notes, and correspondents must be able to change or modify it at will;
# It must be applicable to telegraph communications;
# It must be portable, and should not require several persons to handle or operate;
# Lastly, given the circumstances in which it is to be used, the system must be easy to use and should not be stressful to use or require its users to know and comply with a long list of rules.

Some are no longer relevant given the ability of computers to perform complex encryption. The second rule, now known as '''Kerckhoffs's principle''', is still critically important.<ref name="cryptocom" />