METHOD AND APPARATUS FOR ENCRYPTING AND FOR DECRYPTING DATA ARRANGED IN A DATA SECTOR

摘要

One type of DVD disc is called DVD ROM and intended for use in a DVD ROM drive which is part of a PC. The DVD disc suppliers are interested in encrypting DVD data in order to prohibit unauthorized use of the data. In a computer, the DVD ROM drive has the capability to copy data onto another storage media where it could be pirated. When encoding a disc, the error correction and/or error detection bits (ICP) are exchanged with normal data (MD) or data words are replaced by transformed data words. The reverse processing is carried out when replaying the disc. When this scrambled data is output from a standard DVD ROM drive, the data in the check byte area is lost and the information is not useable.