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Check MD5 Hash on your Mac

October 13th, 2009 - How to, Tips & Tricks

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.

Posted by: Bill Ellis

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Comments:

Comments: 4

Comment from DogsRULE
Time: October 13, 2009, 12:15 pm

the only reason to use MD5 on a Mac is for torrents

Comment from Woodgie
Time: October 13, 2009, 1:34 pm

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.

Pingback from Check MD5 Hash on your Mac | Daily Tips for You
Time: October 13, 2009, 7:11 pm

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Time: October 15, 2009, 10:29 am

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October 13th, 2009