The MD5 Message-Digest Algorithm is a widely used cryptographic hash function that produces a 128-bit hash value. The MD5 hash (or checksum) functions as a compact digital fingerprint of a file. As with all such hashing algorithms, there is theoretically an unlimited number of files that will have any given MD5 hash. However, it is unlikely that any two non-identical files will have the same MD5 hash.

Virtually any change to a file will cause its MD5 hash to change; therefore md5sum is used to verify the integrity of files. Most commonly, md5sum is used to verify that a file has not changed as a result of file transfer, disk error or meddling.

  • Windows:
  • Mac OS X:
    • Download both the file and the corresponding .md5 to the same directory.
    • Start a terminal (Applications -> utilities -> Terminal) and cd to the correct directory
    • Run: md5 -r filename
    • Run: more filename.md5
    • Compare the hashes and make sure that they are identical
  • Linux:
    • Download both the file and the corresponding .md5 to the same directory.
    • Start a terminal and go to the correct directory.
    • Run: md5sum -c filename.md5