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> CRC != checksum in any way shape or form. Check with your professor.

CRC is a function that produces a checksum. See:
http://en.wikipedia.org/wiki/Cyclic_redundancy_check


saqib
http://www.full-disk-encryption.net

Saqib Ali wrote:
>> CRC != checksum in any way shape or form. Check with your professor.
>
> CRC is a function that produces a checksum. See:
> http://en.wikipedia.org/wiki/Cyclic_redundancy_check
>
>
> saqib
> http://www.full-disk-encryption.net
>

If you get your learning from Wiki you are in a sorry state.
The Wiki entry is incorrect in it's terminology. A "checksum"
is the 1's complement of the sum of all preceding bits. A
drop in of zeros of any length will not produce an invalid
checksum. I'm sure you can see that.

However, a drop in of any number of zero bytes will produce
an invalid result when using a CRC.

This is really just a language problem caused because true
'checksum' is so rare these days.

Rick Merrill <> (07-01-04 11:46:03):

> If you get your learning from Wiki you are in a sorry state. The Wiki
> entry is incorrect in it's terminology. A "checksum" is the 1's
> complement of the sum of all preceding bits. A drop in of zeros of any
> length will not produce an invalid checksum. I'm sure you can see
> that.
>
> However, a drop in of any number of zero bytes will produce an invalid
> result when using a CRC.
>
> This is really just a language problem caused because true 'checksum'
> is so rare these days.

Still it's unclear what you mean. You're talking about noise and a CRC
for encrypting. Yes, CRC is supposed to detect noise, but it can't be
used in any way in a cryptographic application. Cryptographic hash
functions are your friends there.


Regards,
E.S.