Abstract: The present invention relates to an encryption method for encrypting information including a series of multiple unit blocks, one at a time, a decryption method for decrypting multiple encrypted unit blocks, one at a time, and a recording and reproducing apparatus that uses those methods. The seed of an encryption key for encrypting each unit block and the seed of an encryption key for decrypting each encrypted unit block, which are used by those methods and the recording and reproducing apparatus, are based on a unit block that is one or more unit blocks before the current unit block in a reproduction order or on information generated by encrypting one or more unit blocks before the current unit block. Alternatively, the seed of an encryption key for encrypting each unit block and the seed of an encryption key for decrypting each encrypted unit block are information based on an encryption key for encrypting a unit block before the current unit block in a reproduction order.

Abstract: A recording apparatus generates key information based at least on contents reproduction permission information, encrypts contents based on the key information, and records the encrypted contents and recording date/time information on a recording medium. A reproducing apparatus reads the encrypted contents and the recording date/time information from the recording medium, acquires reproduction date/time information on the encrypted contents and, based on the recording date/time information that was read, the reproduction date/time information, and reproduction permission limit information on the encrypted contents, generates contents reproduction permission information indicating that the encrypted contents maybe reproduced. The reproducing apparatus generates key information based at least on the contents reproduction permission information and decrypts the encrypted contents that were read.

Abstract: Executes a re-encoding after decoding data of a connection section A of a first MPEG picture data. This re-encoding is executed based on a control such that a transition of a VBV buffer occupation value starts from a VBV buffer occupation value at a position a and ends with a VBV buffer occupation value at a position d. Up to the position a of the first MPEG picture data, the first MPEG picture data is reproduced. Next, re-encoded MPEG picture data of the connection section A is reproduced. Thereafter, the data is connected to the position d of a second MPEG picture data, and the second MPEG picture data of the position d and after is reproduced.

Abstract: Data C generated by scrambling user-desired digital data P and a control word CWp corresponding to the number of reproductions p are recorded on recording media. When creating a master, a user has already been charged for the number of reproductions p. A decryption block decrypts the control word CWp, which is read from the recording media, to CW0. A de-scrambler uses the decryption control word CW0 to decrypt the digital data P for output to a reproduction unit. After confirming the end of reproduction, the decryption block writes a control word CW(p−1) back to the recording media. The recording media may be reproduced p times with no need for communication between a reproduction device and an accounting manager.

Abstract: A signal representative of a key is generated from authenticator-value information and key base information. The authenticator-value information represents a specified authenticator value. The key base information contains identification information which is set to reproduce the specified authenticator value according to a predetermined degeneration function. Contents information is encrypted into encryption-resultant contents information in response to the key signal. The key base information and the encryption-resultant contents information are transmitted or recorded.

Abstract: Bits of a first bit sequence are rearranged in a first matrix according to a predetermined arrangement rule. The first bit sequence represents information being a base of a key. Blocks are formed in the first matrix. Each of the blocks has bits, the number of which is smaller than the number of bits composing the first matrix. Logical operation is executed among bits in each of the blocks, and a bit being a result of the logical operation is generated. The logical-operation-result bits are combined into a second bit sequence. The number of bits composing the second bit sequence is smaller than the number of bits composing the first bit sequence. There is a second matrix composed of predetermined third bit sequences. The second matrix is accessed and one is read out from among the third bit sequences in response to the second bit sequence. The read-out third bit sequence is outputted as information representative of the key.

Abstract: A first-key signal representative of a first key is generated from first-key base information being a base of the first key. Contents information is encrypted into encryption-resultant contents information in response to the first-key signal. A second-key signal representative of a second key is generated from second-key base information being a base of the second key. The first-key base information is encrypted into encryption-resultant first-key base information in response to the second-key signal. Second-key-related information is generated from the second-key base information and additional information according to a predetermined function. The encryption-resultant contents information, the encryption-resultant first-key base information, and the second-key-related information are transmitted or recorded.

Abstract: Each musical performance data of a source file includes time data, note data indicative of music sound start or music sound stop at a moment indicated by the time data, and accent data indicative of sound velocity. The time data, the note, and either the music sound start or the music sound stop are recorded in a first recording area in accordance with the time data. The accent data is recorded in a second recording area. The second recording area is separated from the first recording area. The recorded data in the first and second areas are combined to obtain a target file. And, the another file is recorded in a recording medium. A reproducing apparatus reproduces the recorded musical performance data. The musical performance data are decoded and temporarily stored into a storage medium. The decoded and temporarily stored data are controlled such that the note and accent data are reproduced before the control data.