The part that gets me is when he says "this is it" and then adds on, "oh by the way, it can be reversed or started with different initial conditions," and doesn't give a clear answer of what the final way of calculating a CRC32 checksum given all of the changes he just added. Is there a simpler explanation of how CRC32 is calculated?

After doing some research on the CRC-32 algorithm, I got to the following: /* Usage: Recursively call this with previous crc. Start with crc = 0. */ #define POLYNOMIAL 0x04C11DB7 unsigned int crc...

An advantage of CRC32 or MD5 is they can be calculated as the data passes. Reversing the data means you have to store it all buffered until you go back through the bits in reverse order. MD5 is more calculation intensive - more designed for signing a message than checking for errors because CRCs are easier to contrive a set of data that will ...

Aug 11, 2008 · To compute the Crc32 of a string, you need to convert it to a byte array. Which encoding to use depends on where your string comes from: var text = "target string"; var crc32 = new System.IO.Hashing.Crc32(); var bytes = Encoding.UTF8.GetBytes(text); crc32.Append(bytes);

May 20, 2017 · Of course CRC32 does shifting too, but it only hides the problem under the rug. I.e. it will distribute keys unevenly, there will be heavy clustering at some region. It may appear such hash works fine, until you hit that region, and suddenly your O(1) hash table turns into the O(n) one. CRC32 was designed for detecting damaged files, not hashing.

Oct 28, 2014 · The CRC32 found in zip and a lot of other places uses the polynomial 0x04C11DB7; its reversed form 0xEDB88320 is perhaps better known, being often found in little-endian implementations. CRC32C uses a different polynomial (0x1EDC6F41, reversed 0x82F63B78) but otherwise the computation is the same.

Apr 7, 2013 · As per answer by apm on php.net: "I have verified that the output of the "crc32" is the ITU I.363.5 algorithm (a.k.a. AAL5 CRC - popularised by BZIP2 but also used in ATM transmissions - the algorithm is the same as that in POSIX 1003.2-1992 in Cksum but that stuffs the size into the CRC at the end for extra measure).

I'm trying to calculate/generate the CRC32 hash of some random strings using Python but they do not match the values I generate from online sources. Here is what I'm doing on my PC, >>> import binascii >>> binascii.crc32('hello-world') -1311505829 Another approach, >>> import zlib >>> zlib.crc32('hello-world') -1311505829

Jan 7, 2014 · The x86 CRC32 instruction uses CRC32C. You could create simple program to generate your own references if needed. You still need a pre-baked reference like Mark's answer to reference check your reference checker. –

Jan 10, 2017 · I have been trying to get my head around CRC32 calculations without much success, the values that I seem to get do not match what I should get. I am aware that Python has libraries that are capab...