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CipherSaber - A 'political' encryption cipher

42 pointsby zacharyvoaseover 12 years ago

5 comments

dchestover 12 years ago
The more "politically correct" way to encrypt something would be to do it <i>without using encryption</i>.<p><a href="http://people.csail.mit.edu/rivest/Chaffing.txt" rel="nofollow">http://people.csail.mit.edu/rivest/Chaffing.txt</a><p>Basically, use message authentication algorithm with shared secret to authenticate correct message bits and their position, and output random values for incorrect message bits.<p>For example, to encrypt 2-bit message '10':<p><pre><code> 1: (1, 2388) -- '2388' is a correct MAC(key, 1||1) 1: (0, 3777) -- '3777' is a random number 2: (1, 9796) -- '9796' is a random number 2: (0, 4786) -- '4786' is a correct MAC(key, 2||0) </code></pre> Your full message is transmitted as plain text bits + authentication tag, intermixed with opposite bits + random data. Someone not knowing the secret key cannot guess which bits are the correct message bits, and which are incorrect.<p>To "decrypt", the receiver just calculates authentication tags with the same key, and keeps those bits that correctly authenticate, discarding the ones that don't authenticate.<p>The easiest to memorize and implement MAC, I think, is SipHash which uses 128-bit keys and outputs 64-bit tags: <a href="https://131002.net/siphash/" rel="nofollow">https://131002.net/siphash/</a>
dfcover 12 years ago
<i>"As we face a real threat of a ban on the distribution of strong cryptography, in the United States"</i><p>When I first read this I said "Really? The cryptowars ended a long time ago." and then I saw the last modified date on the home page: 2002. This was when the cryptowars were finally coming to an end...
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zokierover 12 years ago
See also Solitaire, a cipher designed by Bruce Schneier to be applied by hand.<p><a href="http://www.schneier.com/solitaire.html" rel="nofollow">http://www.schneier.com/solitaire.html</a>
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mrgoldenbrownover 12 years ago
The main idea is interesting, but the justification for the name - that Jedi Knights built their own light sabers as a reaction to an Empire - does not sound correct. The Jedi were around long before Emperor Palpatine was destroying the Republic.
B-Conover 12 years ago
It's a boring political tie-in, even if the implications are interesting:<p>&#62; Its political aspect is that because it's so simple, it can be reimplemented anywhere at any time, and so it provides a way for users to communicate privately even if government or other controls make distribution of normal cryptographic software completely impossible.<p>Basically it just means that it's a cheap to run and easy to use algorithm.<p>The interesting implication is that this may make it pointless for "relatively free" nations to ban cryptography. The vast quantities of good, publicly accessible crypto would make it an impossible rule to enforce (although it would give them a leg up in a courtroom setting).