Method of and system for encrypting digital data, method of and apparatus for reproducing digital data, and computer product

• US 7,330,980 B2
• Filed: 04/30/2002
• Issued: 02/12/2008
• Est. Priority Date: 05/11/2001
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nasu, Masami
• Primary Examiner(s): REVAK, CHRISTOPHER A
• Application Number:
  US10/134,630
• Publication Number:
  US 20020168068A1
• Time in Patent Office: 2,114 Days
• Field of Search: 713/193
• US Class Current: 713/193
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

There is provided an input unit which reads copyright digital data stored in a recording medium such as a CD-ROM, an operation unit which performs encryption of digital data based on an encryption algorithm from a plurality of encryption algorithms. A file unit outputs the digital data encrypted by the operation unit and an index value and the encryption operation equation generation parameter into one file. A reproducing apparatus obtains an encryption operation equation from the index value and the encryption operation equation generation parameter in this same file and reproduces the encrypted digital data.

Claims

1. A digital data encryption system comprising:

an operation unit which receives digital data and encrypts the digital data in accordance with a predetermined encryption algorithm and an encryption operation equation determined based on an encryption operation equation generation parameter; and

a file unit which generates a file by combining the digital data encrypted by the operation unit with an index value capable univocally of determining the encryption algorithm and the encryption operation equation generation parameter used for encryption of the digital data,

wherein the operation unit is configured to embed a data manipulation detection code in at least one of various locations in the digital data based on the predetermined encryption algorithm prior to the encryption of the digital data, in order to enable the detection of an illegal manipulation of the digital data.

2. The digital data encryption system according to claim 1, further comprising a setting unit which registers a plurality of encryption algorithms;

and selecting unit which selects an encryption algorithm registered in the setting unit as the predetermined encryption algorithm,

wherein the operation unit encrypts the digital data based on the predetermined encryption algorithm.

3. The digital data encryption system according to claim 1, wherein

the operation unit selects the encryption algorithm and the encryption operation equation generation parameter used for actual encryption from a plurality of encryption algorithms and a plurality of encryption operation equation generation parameters prepared in advance, respectively, and conducts the encryption processing using the selected encryption algorithm and the selected encryption operation equation generation parameter.

4. The digital data encryption system according to claim 1, wherein

the file unit is configured to combine a meaningless data string with the index value of the encryption algorithm and the encryption operation equation generation parameter within the file which includes the encrypted digital data.

5. A digital data reproducing apparatus which decodes and reproduces copyright digital data from encrypted digital data generated by a digital data encryption system, the digital data encryption system including

an operation unit of the encryption system which receives digital data and encrypts the digital data in accordance with a predetermined encryption algorithm and an encryption operation equation determined based on an encryption operation equation generation parameter,

wherein the operation unit is configured to embed a data manipulation detection code in at least one of various locations in the digital data based on the predetermined encryption algorithm prior to the encryption of the digital data, in order to enable the detection of an illegal manipulation of the digital data;

and

a file unit which generates a file by combining the digital data encrypted by the operation unit with an index value capable univocally of determining the encryption algorithm and the encryption operation equation generation parameter used for encryption of the digital data,

the digital data reproducing apparatus comprising;

a read unit which fetches the encrypted digital data from the file;

an operation unit of the reproducing apparatus which determines an index value of an encryption algorithm and an encryption operation equation based on the encryption operation equation generation parameter in the file, and decodes the encrypted digital data in accordance with the encryption operation equation to obtain decoded digital data; and

a reproducing unit which reproduces and the decoded digital data.

6. The digital data reproducing apparatus according to claim 5, wherein

the operation unit determines whether the encrypted digital data is manipulated based on whether a specific data manipulation detection code embedded in the digital data prior to encryption is detected in a location corresponding to the index value of the encryption algorithm and if the operation unit determines that the encrypted digital data is manipulated, the encrypted digital data is not reproduced.

7. A digital data encryption method comprising:

receiving digital data and encrypting the digital data in accordance with a predetermined encryption algorithm and an encryption operation equation determined based on an encryption operation equation generation parameter; and

generating a file by combining the digital data encrypted by the operation unit with an index value capable univocally of determining the encryption algorithm and the encryption operation equation generation parameter used for encryption of the digital data,

wherein the encryption of digital data includes embedding a data manipulation detection code in at least one of various locations in the digital data based on the predetermined encryption algorithm prior to the encryption of the digital data, in order to enable the detection of an illegal manipulation of the digital data.

8. The digital data encryption method according to claim 7, wherein

at the encryption of digital data, the encryption algorithm and the encryption operation equation generation parameter used for actual encryption are selected from a plurality of encryption algorithms and a plurality of encryption operation equation generation parameters prepared in advance, respectively, and the encryption of the digital data is conducted using the selected encryption algorithm and the selected encryption operation equation generation parameter.

9. The digital data encryption method according to claim 7, wherein

the encryption of digital data includes combining a meaningless data string with the index value of the encryption algorithm and the encryption operation equation generation parameter within the file which includes the encrypted digital data.

10. A digital data reproducing method for decoding and reproducing copyright digital data from encrypted digital data generated by a digital data encryption method, the digital data encryption method including

receiving digital data and encrypting the digital data in accordance with a predetermined encryption algorithm and an encryption operation equation determined based on an encryption operation equation generation parameter,

wherein the encryption of digital data includes embedding a data manipulation detection code in at least one of various locations in the digital data based on the predetermined encryption algorithm prior to the encryption of the digital data, in order to enable the detection of an illegal manipulation of the digital data;

and

generating a file by combining the digital data encrypted by the operation unit with an index value capable univocally of determining the encryption algorithm and the encryption operation equation generation parameter used for encryption of the digital data,

the digital data reproducing method comprising;

fetching the encrypted digital data from the file;

determining an index value of an encryption algorithm and an encryption operation equation based on the encryption operation equation generation parameter in the file, and decoding the encrypted digital data in accordance with the encryption operation equation to obtain decoded digital data; and

reproducing the decoded digital data.

11. The digital data reproducing method according to claim 10, wherein

at the determining the index value, it is determined whether the encrypted digital data is manipulated based on whether a specific data manipulation detection code embedded in the digital data prior to encryption is detected in a location corresponding to the index value, and if it is determined that the encrypted digital data is manipulated, the encrypted digital data is not reproduced.

12. A computer readable medium for storing instructions, which when executed on a computer, causes the computer to realize a digital data encryption method including

receiving digital data;

encrypting the digital data in accordance with a predetermined encryption algorithm and an encryption operation equation determined based on an encryption operation equation generation parameter; and

generating a file by combining the digital data encrypted by the operation unit with an index value capable univocally of determining the encryption algorithm and the encryption operation equation generation parameter used for encryption of the digital data,

wherein the encryption of digital data includes embedding a data manipulation detection code in at least one of various locations in the digital data based on the predetermined encryption algorithm prior to the encryption of the digital data, in order to enable the detection of an illegal manipulation of the digital data.

13. A computer readable medium for storing instructions, which when executed on a computer, causes the computer to realize a digital data encryption method and a digital data reproducing method,

the digital data encryption method including

receiving digital data;

encrypting the digital data in accordance with a predetermined encryption algorithm and an encryption operation equation determined based on an encryption operation equation generation parameter;

generating a file by combining the digital data encrypted by the operation unit with an index value capable univocally of determining the encryption algorithm and the encryption operation equation generation parameter used for encryption of the digital data,

the digital data reproducing method including fetching the encrypted digital data from the file;

determining an index value of an encryption algorithm and an encryption operation equation based on the encryption operation equation generation parameter in the file, and decoding the encrypted digital data in accordance with the encryption operation equation to obtain decoded digital data; and

reproducing the decoded digital data,

wherein the encryption of digital data includes embedding a data manipulation detection code in at least one of various locations in the digital data based on the predetermined encryption algorithm prior to the encryption of the digital data, in order to enable the detection of an illegal manipulation of the digital data.