Maybe a stupid question regarding input output fed hash algorithms

jonas.t_at_bredband.net
Date: 08/21/03 

Date: Thu, 21 Aug 2003 08:20:18 +0200

If i feed MD5 with another MD5 output e.g 128 bit.

Is it possible to backtrack the original 128 bit string, is the output from
MD5 carrying such features that will make it possible to reverse a
stream/chain of MD5 fed loop.

Of course i realise that such a chain of linear input output doesn't make
sense to use in a stream cipher.
However if i start out with three MD5 buffers and let the outputs inputs
rotate between the buffes and only use one of the output buffers for use as
a linear streamcipher, do MD5 carry such features that it is possible to
reverse it *if you know* that it is fed by a MD5 string.

I also wonder if this kind of rotating input output buffers could be used to
create streams from other hash algorithms.

Maybe it is alltogether a very bad idea overall but if so i would like to
know why, i'm a bit clueless since it seems like a good idea to me.

BR JT

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