If you are looking for a way to unlock your Samsung Galaxy S4 or Samsung Galaxy Note 3, here is how you can do it on your own using the leaked code. The leaked code that has been making its rounds on the internet is said to have been leaked by an insider.
To use the code, you will first need to fit in a new SIM card. Restart the device and open up the dial pad. Now key in the unlock code, *#197328640. Next, select UMTS >  Debug Screen >  Phone Control >  Network Lock > Options  Perso SHA256 OFF.
Now, wait for 30 seconds before you select Back to enter the Main Menu once more. From there, Now select  NW Lock NV Data INITIALLIZ. Your Samsung device should be unlocked now.
It is also said that the code will also work on some of the older Samsung devices like the Samsung Galaxy S3 and Galaxy Note 2.