Editing Cyclic redundancy check (section)

== Application ==
A CRC-enabled device calculates a short, fixed-length binary sequence, known as the ''check value'' or ''CRC'', for each block of data to be sent or stored and appends it to the data, forming a ''codeword''.

When a codeword is received or read, the device either compares its check value with one freshly calculated from the data block, or equivalently, performs a CRC on the whole codeword and compares the resulting check value with an expected ''residue'' constant.

If the CRC values do not match, then the block contains a data error.

The device may take corrective action, such as rereading the block or requesting that it be sent again. Otherwise, the data is assumed to be error-free (though, with some small probability, it may contain undetected errors; this is inherent in the nature of error-checking).<ref name="ritter-1986">{{Cite journal|first=Terry|last=Ritter|title=The Great CRC Mystery|url=http://www.ciphersbyritter.com/ARTS/CRCMYST.HTM|access-date=21 May 2009|journal=[[Dr. Dobb's Journal]]|date=February 1986|volume=11|issue=2|pages=26–34, 76–83|archive-date=16 April 2009|archive-url=https://web.archive.org/web/20090416095111/http://www.ciphersbyritter.com/ARTS/CRCMYST.HTM|url-status=live}}</ref>