To Hide Windows 7 Wireless Network Security Key

The way is to find the key in the registry where you can unlock the viewing of the WIFI Key.

For that, you have to find a Key where the value is "CElevateWlanUi"

In my case, it was in HKEY_CLASSES_ROOT\Appid\{86F80216-5DD6-4F43-953B-35EF40A35AEE}.
Under this key you have 3 values :
The first one (default) with the value "CElevateWlanUi"
The second one AccessPermission of type Reg_Binary with a binary value (does'nt matter to understand what it means)
The third one is called DllSurrogate with a null value.

The way I solved the problem is to setup the authorizations of the main Key {86F80216-5DD6-4F43-953B-35EF40A35AEE} by a right-click, then "autorizations".
After you have to take possession of this key.
I setup the owner as our domain administrator.
For that click on the the button "Advanced" then on the tab "owner" and replace TrustedInstaller by the administrator of my domain.
Then, I came back to the main panel of authorizations of the main key.
I deleted the entry LAP505\administrators and the entry LAP505\domain users, and added the entry for my domain administrator with all rights. (LAP505 is the computer name)
I applied all the modifications.
I repeated the operation for the second occurence of the key :
HKEY_LOCAL_MACHINE\Software\classid\Appid\{86F80216-5DD6-4F43-953B-35EF40A35AEE}

And when I logged on with a user with local admin privileges, I could connect to WIFI network, I could access to the network center but I could'nt unmark the "Hide caracters". It works!

Second point : As my users want also to connect their laptop at home on their box, I checked the possibility to add a WIFI connection and it worked also! The only restriction is that they can't see the key once it is entered (for modification, they have to delete the connection a re-create it.
I hope it will help you!"