Cryptography – Video cryptography – Copy protection or prevention
Reexamination Certificate
1998-04-14
2001-07-03
Barron, Jr., Gilberto (Department: 2131)
Cryptography
Video cryptography
Copy protection or prevention
C380S045000, C380S239000, C380S278000
Reexamination Certificate
active
06256391
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an enciphering apparatus and method, a deciphering apparatus and method and an information processing apparatus and method, and more particularly to an enciphering apparatus and method, a deciphering apparatus and method and an information processing apparatus and method by which high security is assured.
2. Description of the Related Art
Recently, a network is available which is composed of a plurality of electronic apparatus represented by AV apparatus, computers and so forth which are connected to each other by a bus so that various data may be communicated between them.
Where a network of the type mentioned is employed, for example, data of a movie reproduced from a DVD (Digital Video Disk or Digital Versatile Disk) by a DVD player connected to the network can be transferred through the bus to and displayed by a display unit such as a television receiver or a monitor. Usually, it is licensed from the proprietor of copyright at a point of time when a DVD is purchased to display and enjoy a movie reproduced from the DVD on a display unit.
However, it is not usually licensed from the proprietor of copyright to copy data reproduced from the DVD onto another recording medium and utilize the same. Thus, in order to prevent data sent out through the bus (network) from being copied illegally, it is a possible idea to encipher the data on the sending side and decipher the data on the receiving side.
However, consumer electronics apparatus (CE apparatus) such as DVD players and television receivers are normally designed and produced for predetermined objects and are each produced such that it is impossible for a user to modify it or incorporate a different part into it to acquire or alter internal data (change of functions) of the apparatus. On the other hand, for example, in regard to personal computers, the architecture or circuitry is open to the public, and it is possible to add a board or install various application software to add or alter various functions.
Accordingly, in regard to a personal computer, it can be performed comparatively readily to directly access or alter data on an internal bus of the personal computer by adding predetermined hardware or applying a software program. This signifies that, by producing and applying application software, it can be performed readily, for example, to receive data transmitted as ciphered data from a DVD player to a television receiver and decipher or copy the received data by a personal computer.
In other words, a personal computer has a weak connection between a link portion which effects communication via a bus and an application portion which prepares data to be transmitted and utilizes received data, and includes many portions which can be modified physically and logically by a user. In contrast, a CE apparatus has a strong connection between them and includes little portion which allows intervention of a user.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an enciphering apparatus and method, a deciphering apparatus and method and an information processing apparatus and method by which illegal copying of data can be prevented with a higher degree of certainty.
In order to attain the object described above, according to an aspect of the present invention to provide an enciphering apparatus, comprising enciphering means for enciphering data using a cryptographic key, first generating means for generating a first key, second generating means for generating a second key which is changed at a predetermined timing while the data is enciphered, and producing means for producing the cryptographic key using the first key and the second key.
According to another aspect of the present invention, there is provided an enciphering method, comprising the steps of enciphering data using a cryptographic key, generating a first key, generating a second key which is changed at a predetermined timing while the data are enciphered, and producing the cryptographic key using the first key and the second key.
With the enciphering apparatus and the enciphering method, since a cryptographic key is produced using a first key and a second key which is changed at a predetermined timing while data is enciphered, encipherment can be performed with a high degree of security.
According to a further aspect of the present invention, there is provided a deciphering apparatus, comprising receiving means for receiving enciphered data, deciphering means for deciphering the received data using a cryptographic key, first generating means for generating a first key, second generating means for generating a second key which is changed at a predetermined timing while the data is deciphered, and producing means for producing the cryptographic key using the first key and the second key.
According to a still further aspect of the present invention, there is provided a deciphering method, comprising the steps of receiving enciphered data, deciphering the received data using a cryptographic key, generating a first key, generating a second key which is changed at a predetermined timing while the data is deciphered, and producing the cryptographic key using the first key and the second key.
With the deciphering apparatus and the deciphering method, since a cryptographic key is produced using a first key and a second key which is changed at a predetermined timing while data is deciphered, enciphered data can be deciphered with a higher degree of security.
According to a yet further aspect of the present invention, there is provided an information processing system, comprising a plurality information processing apparatus connected to each other by a bus, the information processing apparatus including first information processing apparatus each having a function whose change is not open to a user, and second information processing apparatus each having a function whose change is open to a user, each of the first information processing apparatus including first receiving means for receiving enciphered data, first deciphering means for deciphering the data received by the first receiving means using a cryptographic key, first generating means for generating a first key, second generating means for generating a second key which is changed at a predetermined timing while the data is deciphered, and first producing means for producing the cryptographic key using the first key generated by the first generating means and the second key generated by the second generating means, each of the second information processing apparatus including second receiving means for receiving enciphered data, third generating means for generating the first key, fourth generating means for generating the second key which is changed at a predetermined timing while the data is deciphered, second producing means for producing a first cryptographic key using one of the first key generated by the third generating means and the second key generated by the fourth generating means, third producing means for producing a second cryptographic key using the other of the first key generated by the third generating means and the second key generated by the fourth means, second deciphering means for deciphering the enciphered data received by the receiving means using the first cryptographic key, and third deciphering means for further deciphering the data deciphered by the second deciphering means using the second cryptographic key.
According to a yet further aspect of the present invention, there is provided an information processing method for an information processing system composed of a plurality information processing apparatus connected to each other by a bus, the information processing apparatus including first information processing apparatus each having a function whose change is not open to a user, and second information processing apparatus each having a function whose change is open to a user, comprising the steps performed by each of the first information processing apparatus of receiving encipher
Asano Tomoyuki
Ishiguro Ryuji
Osakabe Yoshio
Osawa Yoshitomo
Sato Makoto
Barron Jr. Gilberto
Frommer William S.
Frommer Lawrence & Haug LLP.
Kessler Gordon
Song Ho S.
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