Check MD5 Hash on your Mac
How to, Tips & Tricks - October 13th, 2009 - 4 Comments
You can easily check the MD5 Hash of any file on your Mac, all you need to do is launch the Terminal and type the ‘md5′ command:
md5 big_huge_file.iso
You’ll be returned with an MD5 Checksum Hash that you can check against the source MD5 code provided to you (or that a friend shares, or whatever). It will look something like this:
MD5(big_huge_file.iso)= 20665acd5f59a8e22275c78e1490dcc7
The part after the = sign is the MD5 hash code that you can compare against the source to be sure that the file has retained it’s integrity through transmission. Very handy when downloading large files!
Alternatively you can use the openssl command to check MD5 checksums on your Mac, like so:
openssl md5 big_huge_file.iso
The data returned to you will be the same whether you use the openssl command or the md5 command, it’s really just a matter of preference.



the only reason to use MD5 on a Mac is for torrents
Nope, it isn’t.
I regularly use it to check if 2 files that outwardly look the same (same size etc.) are actually the same. I’ll also use it (or to be more accurate, SHA1, the same as the hint above. Just substitute SHA1 for MD5 in the openssl command) as a quick and easy way to verify to people that attachments I’m eMailing them have not been tampered with. It’s the same basic theory as using a digital signature.
Then you have http://support.apple.com/kb/DL930 and the like. Yep, Apple themselves use SHA1 (which is really just a ‘more accurate’ version of MD5 (yes, I KNOW how wrong that comment actually is!) to verify the contents of updates to the OS.
It’s also used by online retailers and things like the Fink package manager. I could go on but I realise quite how boring I can be
So no, not just torrents.
[...] more here: Check MD5 Hash on your Mac You can follow any responses to this entry through the RSS 2.0 feed. You can leave a [...]
[...] unofficially at 4% worldwideSnow Leopard Incompatible Software List from AppleMessiest Desktop Ever?Check MD5 Hash on your MacWarning! Obscure Snow Leopard bug deletes entire user accounts!MacBook Keyboard Backlight Controls [...]