Warning! New cryptographic modes!

[Roland Dowdeswell]

On 1241996128 seconds since the Beginning of the UNIX epoch
Jerry Leichter wrote:
>

>So here we have it all:  A new cryptographic mode, documented only in  
>C code, being proposed for broad use with no analysis.
>
>In any case, there are obvious, well-understood solutions here:  Use  
>counter mode, which propagates changes by a single block of the  
>cryptosystem.  Or use any other stream cipher mode.  (An interesting  
>question is whether there's a mode that will recover from insertions  
>or deletions.  Perhaps something like:  Use counter mode.  If two  
>consecutive ciphertext bytes are 0, fill the rest of the ciphertext  
>block with 0's, jump the counter by 65536, and insert a special block  
>containing the new counter value.)

I'm not convinced that a stream cipher is appropriate here because
if you change the data then you'll reveal the plaintext.

--
    Roland Dowdeswell                      http://Imrryr.ORG/~elric/

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