EKV (Encrypted Key Values)

In the Left 4 Dead branch and later there is a new file type with the extension .ekv. These files are encrypted with a game specific ICE key, and are used for video settings that the user shouldn't be able to set. The file to be used is determined by the CPU, GPU, GPU memory and memory specifications. In Alien Swarm this can be an issue, as even though the lower graphical levels do not have film grain, these ekv files will force film grain at higher graphical tiers, along with motion blur and several other ConVars. Thankfully it is quite easy to find the ICE key for these ekv files, and also those for other games, the Alien Swarm videocfg.lib contains the following keys:

Game	ICE Key
Left 4 Dead 1 + 2	zp14Hi(]
Portal 2	UrE66!Ap
Alien Swarm	sW9.JupP
"nimbus"	E2NcUkG
Dota 2 (Now unused?)	dAIt1IL!
Default	X8bU2qll

These keys allow for the ekv files to be decrypted with vice, modified and then re-encrypted. For most mods you would want to use the default key as it is used when the mod name does not match any of the other games. This allows for you to set the different default values of ConVars at the specified CPU, GPU and memory levels.