MD5 Tools on Mac OS and Windows 7

The md5 checksum algorithm is very old and nowadays regarded as “breakable”, to such an extent that it is not recommended for use in data transmission (through interfering environments) protocols.  However it is handy, well-established. and hence warm/fuzzy…

On Mac OS, the ‘md5’ command is inbult to the OS:

  •  Compute an MD5 checksum:
    • $ md5 test.mp4
      • MD5 (test1.mp4) = f3ed1559874599d26fddc5802d65266e
    • $ md5 *
      • MD5 (test1.mp4) = f3ed1559874599d26fddc5802d65266e
      • MD5 (test2.mp4) = b9bfa87a6a126911f2246c7a615bff27
  • For help: [ man md5 ]
  • To check a file against an expected checksum value:
    • md5 -c CHECKSUM.MD5
    • Where CHECKSUM.MD5 has (only) multiple entries (lines) as returned by MD5 command, e.g.:
      • MD5 (test1.mp4) = f3ed1559874599d26fddc5802d65266e
      • MD5 (test2.mp4) = b9bfa87a6a126911f2246c7a615bff27
  • ???

On Windows 7:

  • There is nothing inbuilt to the OS…
  • Third-party applications are available:
    • Probably best to use a non-Microsoft one, e.g. a linux-like one…
    • There are also many user-friendly/convenience (GUI-based checksum applications, offering additional checksum varieties, beyond md5.
    • http://support.microsoft.com/kb/841290
      • The FCIV utility runs on Microsoft Windows 2000, Windows XP, and Windows Server 2003
        • No mention of Windows 7 but that was after its time(2004) so maybe still worth a try?
      • Download link:
      • The Microsoft File Checksum Integrity Verifier (FCIV) utility is an unsupported command-line utility that computes MD5 or SHA1 cryptographic hashes for files. Microsoft does not provide support for this utility. Use this utility at your own risk. Microsoft Product Support Services (PSS) cannot answer questions about the File Checksum Integrity Verifier utility.
        • Weird!  Why would they maintain such a …discouraging… attitude?
      • For help: [ fciv.exe /? ]
      • Capabilities:
        • Supports MD5 or SHA1 hash algorithms (The default is MD5.)
        • Can output hash values to the console or store the hash value and file name in an XML file
        • Can recursively generate hash values for all files in a directory and in all subdirectories (for example, fciv.exe c:\ -r)
        • Supplies an exception list to specify files or directories to hash
        • Can store hash values for a file with or without the full path of the file
    • ?

This entry was posted on Friday, October 18th, 2013 at 09:59 and is filed under checksum, Mac, Windows, Windows 7. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.

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