I get my key, but have one problem: The Game not Start.
How I resolve it:
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Go to game folder, in “Binaries” and “Win32” (G:\Program Files (x86)\Steam\steamapps\common\Dirty Bomb\Binaries\Win32)
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Change the “ShooterGame-Win32-Shipping.exe” to “Open as administrator” and “Windows 7”
[Right Click > Properties > Compatibility]
Now works. 
I use the “BitDefender 2014”, I need to turn off the Firewall.