What is MD5 and how to use it to verify your download

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LeslieAnn

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Feb 8, 2011
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You have probably seen these below the rom or file you are downloading:
MD5: 4576d484f39792ab0cfb506ea0592150

So what is MD5? MD5 is a number used to make sure two files (yours vs theirs) are the exact same using a mathematical equation. When you download, while the music industry likes to claim that digital downloads are all exactly identical, the truth is, they aren't always. The internet sends everything in bits and parts. Sometimes things get lost along the way. MD5 is used to make sure the files match. It's not just the internet though, many don't realize a file can be corrupted any time it is moved (or even while sitting on your hard disk if it's bad). This includes moving from your computer to the phone, since USB is far from perfect.

So how do we use it?
We need a program that will generate an MD5 sum.
Personally, I use a portable one, meaning it doesn't install anything, it runs from a folder, or thumbstick. You can move it where you like without it breaking.

This is what I use.
WinMd5Sum Portable | PortableApps.com - Portable software for USB, portable and cloud drives


How to check an md5.
Run the installer and tell it a folder to use, your desktop is fine.

Open the folder and run the program.

You should end up with a small little window. Drag the file you want to check onto that window.
The middle line will show you the md5 of your file.

Now, instead of looking at both numbers, copy the md5 the author gave you and past it in the bottom row of that little window, and press compare. It will tell you if they match or not. If they don't then your file is corrupt and you need to download it again.

If you are an author, then you copy the middle one and paste that for others to use.
 

JerryScript

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Mar 8, 2011
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Since there is always the possibility of corruption when transfering from your PC to your phone, I use the phone's built in md5 checksum utility.

Download or transfer via PC/wifi/BT/whatever the file in question to your phone's sdcard. Open Terminal Emulator and type in the following:

su
cd sdcard
md5sum NAME_OF_FILE

It will take about 15-20 seconds to generate the key, which you can then check against the posted one. ;)
 

flapjack.fiasco

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Sep 13, 2011
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File Manager checks MD5s when you long press and select "Details." :)

Which file manager are you talking about? I checked the default one in Mirage, and there's no details option. I checked Root Explorer also, and it calculates the md5 in the properties option. Maybe that's what you were thinking of? Or is there a version of file manager that I'm unfamiliar with?

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