[Haskell-cafe] Digests

[Permjacov Evgeniy]

On 12/03/2010 10:48 AM, Serguey Zefirov wrote:
> 2010/12/3 Permjacov Evgeniy <permeakra at gmail.com>:
>>> Most of the time you can get away with usual block ciphers (and even
>>> with weaker parameters). There is a scheme that transforms block
>>> cipher into hash function:
>>> http://en.wikipedia.org/wiki/CRHF#Hash_functions_based_on_block_ciphers
>> */me wrote it into to_read list. The problem is, however, that block
>> ciphers are quite unfriendly to plain word8 streams. It is not a deadly
>> problem, but i'd like to avoid block collections.
> All one-way hashes do block collections. This is unavoidable.
Why ? Is there some math behind this proposition ?