How to checksum

By  on  

Many of us see the term checksum and checksum outputs frequently but don't really take the time to run them -- oftentimes we simply trust the file we've downloaded is in working order and from the original source.  This past weekend when I was attempting to recover my Bitcoin Cash, however, I wasn't willing to chance it -- I wanted to ensure the app/file hadn't been compromised in any way.

For those who don't know what a checksum is, I think this definition from Lifewire is helpful:

A checksum is the outcome of running an algorithm, called a cryptographic hash function, on a piece of data, usually a single file. Comparing the checksum that you generate from your version of the file, with the one provided by the source of the file, helps ensure that your copy of the file is genuine and error free.

Armed with the file I wanted, and the verified checksum provided by the author, I ran a checksum on the file in question:

shasum 1 logo.png

# shasum: 1:
# e78c5ca49b926a15b3d4e5107f3b17b2cc6fd54b  logo.png

shasum is Mac's command line command for checking checkums.  The first argument represents which sha hash value you want to use (sha-1, sha-256, etc.) . The last argument is the file to check.

When it comes to financial and critical apps and files, it's probably worth your time to run a quick checksum to ensure what you've downloaded is what you really want!

Recent Features

  • By
    Send Text Messages with PHP

    Kids these days, I tell ya.  All they care about is the technology.  The video games.  The bottled water.  Oh, and the texting, always the texting.  Back in my day, all we had was...OK, I had all of these things too.  But I still don't get...

  • By
    From Webcam to Animated GIF: the Secret Behind chat.meatspac.es!

    My team mate Edna Piranha is not only an awesome hacker; she's also a fantastic philosopher! Communication and online interactions is a subject that has kept her mind busy for a long time, and it has also resulted in a bunch of interesting experimental projects...

Incredible Demos

  • By
    Facebook Open Graph META Tags

    It's no secret that Facebook has become a major traffic driver for all types of websites.  Nowadays even large corporations steer consumers toward their Facebook pages instead of the corporate websites directly.  And of course there are Facebook "Like" and "Recommend" widgets on every website.  One...

  • By
    Six Degrees of Kevin Bacon Using MooTools 1.2

    As you can probably tell, I try to mix some fun in with my MooTools madness but I also try to make my examples as practical as possible. Well...this may not be one of those times. I love movies and useless movie trivia so naturally I'm...

Discussion

  1. Thanks for that. I hadn’t had to do it on the Mac side yet but on Windows the equivalent built-in utility is called CertUtil.

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!