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Paper: FITS Checksum Verification in the NOAO Archive
Volume: 77, Astronomical Data Analysis Software and Systems IV
Page: 247
Authors: Seaman, R.
Abstract: There is no standard procedure for verifying the integrity of FITS data files. While a FITS file may be subjected to the same checksum or digital signature calculation as any other data file, the resulting sum or signature must normally be carried separately from the FITS file since writing the value into the header will change the checksum. A simple method for embedding an ASCII coded 32 bit 1's complement checksum within a FITS header (or any ASCII text) is described that is quick to compute and has desirable features such as: the checksum of each FITS file or extension is set to zero; the checksum may be accumulated in any order; and the checksum is easily updated with simple arithmetic. On-line verification of tapes for the NOAO/IRAF Save the Bits archive is discussed as an example.
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