What is an Android key hash?

Question

I tried looking up what an Android key hash on Google.

But all I got was how to generate it, not what actually what it is. Can anybody give a simple explanation of what this key hash actually is and why Facebook needs you to generate one to run samples and your own application?

Answer 1

Can anybody give a simple explanation of what this key hash actually is..

The key hash is a machine specific security check for authenticity. If you use multiple machines for development of the application, you need to add and save multiple key hash to your profile to authenticate every machine.

From the Facebook Documentation page :

..The key hash is used by Facebook as a security check for authenticity . By default, the app's package is signed with a machine specific debug key. When publishing the app it is typically signed with a different, release key. Therefore, you want to make sure you have the hashes of all the related keys set on Facebook...
...Note that you can add multiple key hashes here if you are developing with multiple machines . You will now be able to compile and run all of the authentication-based samples on your emulator without issue.....

(Emphasis mine)

Why does Facebook need you to generate one in order to run samples and your own application?

It's an authentication key to identify registered developers.

Answer 2

How to get key hash of your device?

If your using eclipse then go into window menu > preferences > android > build > then on right side you will get your machines md5 and sha key which is your hash key for facebook i think you need to provide your SHA key as a hash key for facebook

this is the very simple way to get your key hash rather than complex command tool process

what is key hash? it is key associated with your device which is unique key to identify your device so when you provide it to facebook (in your case facebook) then they generte application key against your keyhash so only your machine able to generate the apk with runable output i mean facebook functionality will able to run with its full functionality

such kind of key hash also needed in google project also

NOTE: Never disclose your keyhash to anyone

hope this information will clear your doubts happy coding :)