- VIC cipher
The VIC cipher was a pencil and paper
cipher used by the Sovietspy Reino Häyhänen ,codename d "VICTOR".FAQ
It was arguably the most complex hand-operated cipher ever seen, when it was first discovered. The initial analysis done by the NSA in 1953 did not absolutely conclude that it was a hand cipher, but its placement in a hollowed out 5c coin implied it could be broken by pencil and paper. The VIC cipher remained unbroken until more information about its structure was available.
Although certainly not as complex or secure as modern
computer operatedstream cipher s orblock cipher s, in practice messages protected by it resisted all attempts atcryptanalysis by at leastNSA (and perhaps other organizations such asGCHQ ) from its discovery in1953 until Häyhänen's defection in1957 .A revolutionary leap
The VIC cipher can be regarded as the evolutionary pinnacle of the
Nihilist cipher family.The VIC cipher has several important integrated components, including mod 10 chain addition (a
lagged Fibonacci generator , a recursive formula used to generate a sequence ofpseudorandom digits ), astraddling checkerboard , and a disrupted double transposition.Until the discovery of VIC, it was generally thought that a double transposition alone was the most complex cipher an agent, as a practical matter, could use as a field cipher.
References
* David Kahn, [https://www.cia.gov/library/center-for-the-study-of-intelligence/kent-csi/docs/v05i4a09p_0001.htm Number One From Moscow]
External links
* [http://www.hypermaths.org/quadibloc/crypto/pp1324.htm John Savard's page on the VIC cipher]
* [http://users.telenet.be/d.rijmenants/en/ppc-xx.htm PPC-XX, a variant with four different keying methodes]
* [http://users.telenet.be/d.rijmenants/en/secom.htm SECOM, a VIC variant with extended checkerboard]
* [http://secretcodebreaker.com/history5.html "The Cipher in a Hollow Nickel"]See also
*
Topics in cryptography .
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