Re: [ethmac] CRC Magic number! How to figure out c704dd7b?

[ericsliao@yahoo.com]

Hi,

This number is polynomial dependent, and you can develop it yourself.
As long as you follow the rules of CRC32, you will get it.
It's nature of any polynomial. If poly of CRC32 change, the magical number change as well.
I ever played with it, and found out that every polynomial has his own sweet magical number.

rules I mentioned as above,
1. intial setting of registers
normally you want to set them 1 instead of 0
2. rotating of CRC32
depend on what endian the specification adopt
3. complimenting of CRC32
same as 1, if you don't compliment, you get 0.

have nice day
eric
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