MD5 ALGORITHM

I AM TRYING TO IMPLEMENT AN MD5 algorithm on a PIC 18F452.

Any one done this for a pic before? 16 or 18 series.

we use Proton pic basic and assembler.

Andrew

snipped-for-privacy@btclick.com

Looks like he's got "techniques" down (he got the task done, the message is on the groups he decided it should be on), he "just" needs to learn Netiquette. Unfortunately, it seems many posters read Emily Postnews and take what she writes literally.

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Sorry chaps.

And of course none of you have ever been struggling on a project with 3 days to go and desperately looking for help , some where , any where ............ have you

Thanks for your help I hope some young student just starting out in this game doesn't come across you first and get put off.

Very Best Regards (sorry d>

Apparently it is possible to change data "protected" by MD5 in an undetectable way.

The Chinese research, IIRC was for _selected_ fixed-length pairs of data blocks that generated identical MD5 hashes and this demonstrated that a collision is possible and could be found in a reasonable amount of time. They did _not_ prove that arbitrary data could be arbitrarily altered and yield the same MD5 hash.

While it is possible, given a message and an MD5 hash, to find another message that has the same MD5 hash, it is still extremely difficult to come up with a message that suits the purpose of the attacker and still have the same hash. (i.e., change a speed readout without adding all kinds of other filler to alter the message and get it to hash to the same value)