nvidia-installer --sanity

nvidia-installer --sanity is complaining about several files in our installation, such as this one:

ERROR: The installed file ‘/usr/bin/nvidia-installer’ has a different
checksum (2263010314) than when it was installed (2531969214).

Could someone tell me how the checksums are calculated?

sum, cksum, sha1sum, or md5sum do not give values similar to the ones listed above.