User:Xiong/crc

Common polynomials

 * As well as the polynomial, the prefix and the value exclusive-ORed with the remainder are important for some more complicated checksums (like most forms of CRC-32 and CRC-64).
 * CRCs less than CRC-16 do not tend to use Initial or final XOR values.
 * Very often custom versions of checksums are created by changing these values, as it does not alter the overall mechanics (or math) of the checksum algorithm -- and may provide some nominal security features. However a CRC algorithm can be reverse-engineered from a small number of message-CRC pairs by brute force search.

Note: in this table the high-order bit is omitted; see Specifying a CRC above.

Known to exist, but technologically defunct -- mainly replaced by cryptographic hash functions
 * CRC-128 (IEEE)
 * CRC-256 (IEEE)