CentralNotice From Wikipedia, the free encyclopedia Jump to: navigation , search This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed. (June 2009) ( Learn how and when to remove this template message ) In the history of cryptography , the Nihilist cipher is a manually operated symmetric encryption cipher originally used by Russian Nihilists in the 1880s to organize terrorism against the tsarist regime. The term is sometimes extended to several improved algorithms used much later for communication by the First Chief Directorate with its spies . 1 Description 1.1 Example 2 Nihilist cryptanalysis 3 Later variants or derivatives 4 See also 5 References 6 External links Description [ edit ] First the encipherer constr...