In order to generate key hash you need to follow some easy steps.
1) Download Openssl from: here.
2) Make a openssl folder in C drive
3) Extract Zip files into this openssl folder created in C Drive.
4) Copy the File debug.keystore from .android folder in my case (C:\Users\SYSTEM.android) and paste into JDK bin Folder in my case (C:\Program Files\Java\jdk1.6.0_05\bin)
5) Open command prompt and give the path of JDK Bin folder in my case (C:\Program Files\Java\jdk1.6.0_05\bin).
6) Copy the following code and hit enter
keytool -exportcert -alias androiddebugkey -keystore debug.keystore > c:\openssl\bin\debug.txt
7) Now you need to enter password, Password = android.
8) If you see in openssl Bin folder, you will get a file with the name of debug.txt
9) Now either you can restart command prompt or work with existing command prompt
10) get back to C drive and give the path of openssl Bin folder
11) copy the following code and paste
openssl sha1 -binary debug.txt > debug_sha.txt
12) you will get debug_sha.txt in openssl bin folder
13) Again copy following code and paste
openssl base64 -in debug_sha.txt > debug_base64.txt
14) you will get debug_base64.txt in openssl bin folder
15) open debug_base64.txt file Here is your Key hash.