Editing Great Cipher (section)

{{short description|French cypher that remained unbroken for several centuries.}}
The '''Great Cipher''' ([[French language|French]]: ''Grand chiffre'') was a [[substitution cipher#Homophonic substitution|nomenclator]] cipher developed by the [[Rossignols]], several generations of whom served the [[French monarchs]] as [[cryptographers]]. The Great Cipher was so named because of its excellence and because it was reputed to be unbreakable.

Modified forms were in use by the French [[Peninsular War|Peninsular]] army until the summer of 1811.<ref>Urban 2004, p. 104</ref> After it fell out of current use, many documents in the French archives were unreadable until it was decoded.