The decryption block receives encrypted data and performs a decryption operation using the encryption and decryption key.

An encryption/decryption system includes an encryption device and a plurality of decryption devices.

By means of the present invention, the problem of decryption incapability existing in the visible light encryption and decryption is solved, and the decryption accuracy is improved.

A decryption unit (208) decrypts the encrypted personal information by using the decryption key.

Corresponding decryption operations may be used to decrypt the ciphertext message.

The data packets can be decrypted by means of the decryption keys (48), which are retransmitted a number of times.

In addition the local encryption/decryption parameters are adjusted based on the encryption/decryption changing message.

The program generates a decryption program.

According to the initialization packet, a decryption algorithm is initialized and a decryption key is acquired for decrypting the respective resources.

A decryption apparatus (109) comprises a key stream generator (111) generating a local decryption key stream.

A digital data shuffling/deshuffling system which can prevent the decipherment of information data by an unspecified third person.

The scrambled data are descrambled on the basis of the key information.

The method further includes providing a decrypting key wherein the decrypting key allows the burst to be decrypted.

If the packet is successfully decrypted using the first encryption key, the packet is encrypted using the second encryption and transmitted over the power line.

Normal decrypting operation is modified so that the input plaintext information appears unaltered as plaintext information at the output of the decrypting apparatus.

This invention provides a method and system for decrypting an optical disc.

Normal decrypting operation is modified so that the input plaintext information appears as unaltered plaintext information at the output of the decrypting apparatus.