Re: Varying Ciphertext

Sebastian Gottschalk wrote:
Dane Smith wrote:

Just out of my own curiosity, how do people feel about a block cipher
which encrypts the same message using the same key to any one of many
possible ciphertexts. I'm not entirely sure this has ever been done to
any great length, though, it is quite possible I have missed something.
Does anyone believe that it is even necessarily possible?

It's called and IV (initialization vector) and is supposed to protect
against exactly your scenario: "Hey, that's the same ciphertext. It must
have been the same plaintext encrypted with he same key."

But, assuming you have the same IV, then you still have the same output.
IV's are normally associated with CBC mode in block ciphers, assuming Im
not mistaken. What I am trying to describe is something that with the
same exact input, key, IV, plaintext, would still be able to vary in output.

Dane
.

Relevant Pages

  • Re: Varying Ciphertext
    ... possible ciphertexts. ... each independent block encrypts to something different every time, ... in ECB mode where there is no IV. ...
    (sci.crypt)
  • Re: Varying Ciphertext
    ... Dane Smith wrote: ... which encrypts the same message using the same key to any one of many ... possible ciphertexts. ... Sherman's "Randomized encryption techniques", in the Crypto 82 ...
    (sci.crypt)
  • Re: Varying Ciphertext
    ... which encrypts the same message using the same key to any one of many ... possible ciphertexts. ... How would you decrypt it? ...
    (sci.crypt)
  • Re: Varying Ciphertext
    ... Dane Smith wrote: ... which encrypts the same message using the same key to any one of many ... possible ciphertexts. ... If different cipher text out of the same plain text is important then use a different key and implement a KEA. ...
    (sci.crypt)