I am looking at the MD5 coding routines (and others) and was wondering if the numbers used as the MAGIC numbers for the calls (the 32 bit ones) were arbitary of actually needed to be as they are - while they are whats listed in the RFCs etc can they just be charged to make a personalized version of the MD5 routine? Or is the actual alogorithm reliant on each of the different numbers somehow.

Excuse my non-crypto knowledge here.

Posted on 2003-01-31 19:40:26 by jjoyce
It's possible to choose other numbers for the sub passes of the hash algorithms but it depends on your need.
None of those numbers you are thinking of were chosen at random and there is a alot of math behind them to choose ones which aren't weak. So if you change these numbers without knowledge you most certainly will weaken the algorithm from it's original strength. However there might be cases where it's useful. Your algorithm will still work just produce different results. Lots of comercial programs have modified algorithms of hashes, block ciphers etc. with the purpose to stop crackers from using them as they are. A cracker will still be able to reverse engineer your program and either discover the original algorithm+ modifications or just rip the entire algorithm and re-assemble it.

// CyberHeg
Posted on 2003-02-01 07:40:21 by CyberHeg