[Tutor] Iterate over letters in a word
dyoo at hkn.eecs.berkeley.edu
Tue Mar 14 22:12:39 CET 2006
> As a side note, remember that that xor-ing a key with a message is
> trivial to break (it's just a variation on the Vigenere cipher first
> published in 1568). So don't use if for any real applications.
Counterpoint: think of "one-time pads".
XOR itself is just a technique --- it's just a binary operation between
two bit patterns --- but the use of one-time pads provides unbreakable
encryption. As long as the xor-ing key is protected, and as long as the
encrypting key pattern is as long as the message, it's theoretically
If we reuse the same encrypting bit-pattern over and over, or make the
XORing key less than random, then all bets are off, of course. *grin*
There are different encryption schemes that, at its heart, use XOR. But
XOR itself is not inherently insecure: it's our use of it that determines
the quality of the result.
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