A method is provided to facilitate the detection of file tampering, such as a computer virus, on a computer. In one example, a digital fingerprint is generated for each file on the computer using a substantially collision-free algorithm. The digital fingerprints of the computer files are compared with digital fingerprints of the computer files generated when the files were previously saved. If the digital fingerprint of that file differs from the digital fingerprint generated when that file was previously saved, a computer virus or other tampering may exist on the file.