Abstract: A method and system is provided for selectively denying access to encoded data. Encryption is used to protect secured data on any of a number of media devices in a system and in which unsecured data is not encrypted. The classified data is encrypted and then transmitted for storage on the medium. The encryption key is stored only in volatile memory on the target device connected to the medium during a mission. The encryption key is known only in a location physically distant from the target device during a mission. Resources are provided for mission personnel to immediately delete the encryption key from volatile memory upon perceiving a threat, as well as causing automatic deletion of the encryption key upon a power loss to the target device in order to make the encrypted data unavailable to any personnel (whether authorized or not) at the location of the target device.