MD5 proposal

Poul-Henning Kamp wrote:

> In message <20020325130131.T20936 at isnic.is>, Olafur Osvaldsson writes:
> 
> 
>>>auth:             MD5-PW 4aabd3dbc0746c8a4b5467f99a4f8524
>>>
>>>
>>Why not use md5 crypt wich is already used on many operating systems for
>>passwords?
>>
>>auth:             MD5-PW $1$sD9e4pQn$1832L4.BxsZHusy0plg8i0
>>
> 
> The source can be found here:
> 
>    http://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libcrypt/crypt-md5.c
>


I agree that a salt makes dictionary attacks very hard if not 
impossible. And this is good argument in favour of the Olafur's and 
Poul-Henning's proposal.

My main concern here would be that basing the proposed method on an 
implementation (md5-crypt), which may change or may be mixed with some 
other implementation, rather than on the documented algorithm (md5 
hash), which cannot, may cause confusion in the future.

And, as a side question from a person far from cryptography, is it a 
proved fact that iterative complexity of md5-crypt makes the hash better?

Regards,

Andrei Robachevsky
RIPE NCC