You can enable or disable the function that lets users change the format of a Virtual Smart Card (VSC) personal identification number (PIN) by using the CTRL+ALT+DEL sequence.
To do this, you have to download and apply hotfix from KB2808693.
After you apply this hotfix, you can enable and disable this function.
Works on Windows 8, Windows 7, Windows Server 2008 R2, and Windows Server 2012