Disclosed is apparatus for processing an encrypted data stream within a computer system adapted to receive the encrypted data stream from a data storage device. A data output device is coupled to a computer system and has a plurality of data output areas. An encrypted data stream is transferred from a data storage device to the data output device, the encrypted data stream being for output to one of the plurality of data output areas. The encrypted data stream is received and decrypted to produce a clear data stream for output to one of the plurality of data output areas. A decryption means receives a decryption key from the computer system, the decryption key relating only to the encrypted stream associated with the one of the plurality of data output areas.