CRC is the abbreviation used to describe the cyclic redundancy check. This test is utilized to make an equation of all data contained within the compressed file. It calculates the CRC every time the file is added to an archive.

The CRC number itself doesn't provide any information on whether the data is corrupted or not; therefore, if you look through for metadata in your compressed file or archive and see a CRC value, it does not necessarily mean that your archive has been damaged. The metadata only displays this initial estimated CRC.