

CipherSaber - A 'political' encryption cipher - zacharyvoase
https://en.wikipedia.org/wiki/CipherSaber

======
dchest
The more "politically correct" way to encrypt something would be to do it
_without using encryption_.

<http://people.csail.mit.edu/rivest/Chaffing.txt>

Basically, use message authentication algorithm with shared secret to
authenticate correct message bits and their position, and output random values
for incorrect message bits.

For example, to encrypt 2-bit message '10':

    
    
        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)
    

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.

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.

The easiest to memorize and implement MAC, I think, is SipHash which uses
128-bit keys and outputs 64-bit tags: <https://131002.net/siphash/>

------
dfc
_"As we face a real threat of a ban on the distribution of strong
cryptography, in the United States"_

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...

~~~
Bockit
For anyone else who thought, "What, there was a period of time known as the
cryptowars?" and wants to know more, I found this article gave a decent
rundown[1].

[1]: <http://www.fipr.org/press/050525crypto.html>

~~~
tjaerv
The definitive account is Steven Levy's book "Crypto":

[http://www.amazon.com/Crypto-Rebels-Government-Privacy-
Digit...](http://www.amazon.com/Crypto-Rebels-Government-Privacy-
Digital/dp/0140244328)

------
zokier
See also Solitaire, a cipher designed by Bruce Schneier to be applied by hand.

<http://www.schneier.com/solitaire.html>

~~~
batgaijin
well, today encrypting the message within the deck is just not dense enough
information wise.

why don't people just use a shuffled deck as a one time pad key for encrypted
files? seems like a much better application of the idea.

~~~
capnrefsmmat
How do you turn a shuffled deck into a key long enough to encrypt a file?

~~~
batgaijin
the order of the shuffled deck is 52!

~~~
algorias
A one time pad consumes as many bits as the message length. It has nothing to
do with the bits of information that can theoretically be stored in a deck of
cards.

~~~
batgaijin
use something like pi to create a number of specific length (twice as long as
the file?) and permute it according to the card order?

------
mrgoldenbrown
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-Con
It's a boring political tie-in, even if the implications are interesting:

> 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.

Basically it just means that it's a cheap to run and easy to use algorithm.

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).

