Encryption/decryption of program data but not PSI data

The receiver receives data from the transmitter key. The data key is generated by a random number generator seed as a seed obtained from the data to be encrypted in the transmitter. The receiver also receives a synchronization signal in place of a null packet in the MPEG transport stream, and receives the encrypted data in the MPEG transport stream, and in response to the received synchronization signal, use of the data key to decrypt the received encrypted data to synchronize. Additionally or alternatively, the successive first, second, third and fourth by using a triple wrap decoding techniques and messages that are encrypted with the encrypted parts of the first, second, third and fourth decoded data The decoding part.Data key, a transmitter, a receiver, transport streams, encryption, decryption