On Tue, 3 Sep 2013 14:41:49 +0100, Costin Enache wrote:
>
>>The password phrase hash can be split into blocks of 8 bytes, and each of
>>them "cracked" independently, also in parallel.
>>
>Sounds like a half-hearted implementation -- what would have been the
>additional cost of using larger blocks?
>
So I look at:
http://en.wikipedia.org/wiki/Data_Encryption_Standard
(Yah, I know; "Wikipedia"), which says:
Like other block ciphers, DES by itself is not a secure means of encryption
but must instead be used in a mode of operation. FIPS-81 specifies several
modes for use with DES.[20] Further comments on the usage of DES are
contained in FIPS-74.[21]
And from FIPS-81:
http://www.itl.nist.gov/fipspubs/fip81.htm
which seems to be rife with typos, confusing "zero" with "oscar" (not even
"Oscar"), it would appear that the passphrase handling is using the simplest
method, ECB, which is susceptible to paralleization. Other methods, CBC,
CFB, and OFB would seem to resist parallelization and to be stronger.
>Not possible directly with DES, but there are many other alternatives
>which would be quite secure at no additional cost. I have no idea why
>the password phrase is encrypted in this way, considering the available
>modern technology already employed by RACF.
I see.
-- gil
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