How do I detect if a file on my USB drive was tampered with?

Discussion in 'OS X Yosemite (10.10)' started by moonman239, Jan 17, 2015.

  1. moonman239 macrumors 68000

    Mar 27, 2009
    If I should lose my drive, I don't care if someone sees what's inside. I do care, however, if somebody managed to tamper with any one of my files without my permission.

    If there's a program that will run on Windows and Mac that I can load onto my USB drive, that would be fine. You know what? I could create one, using my Java skills - after all, it's a pretty safe bet that every device into which a USB drive is plugged will have a Java runtime environment of some kind installed.
  2. jc1350 macrumors 6502a

    Feb 4, 2008
    In terminal, run this command:

    openssl sha256 path/to/filename

    You wil need to know the valid/correct digest/hash so you have something to which you can compare the results.

    If you don't want to fool with terminal, you can get a Finder extension or whatever called HashTab. I have an older (free) version and it's excellent (although I'm a command line junkie and usually use BASH aliases for the openssl commands).

    Hashtab is now available on Mac only in the App store, but it's only $1.99. Worth it if you deal with file hashes and even a semi-regular basis.
  3. Natzoo macrumors 65816


    Sep 16, 2014
    Not sure where i am
    I am a noob to terminal, how do you get so good with it? any tips
  4. leman macrumors G3

    Oct 14, 2008
    Like any other thing, practice

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