Copy protection method and system for digital media
First Claim
1. A copy protection method for digital media, the method comprising:
- (a) encrypting an original media data set with a symmetric algorithm corresponding to an original media key;
(b) generating an intermediate key by encrypting said original media key with a media identification;
(c) encrypting said intermediate key with a public key of a compliant playing device;
(d) delivering said encrypted media data set, said encrypted intermediate key, and a media certificate to said playing device, said certificate including a private key identification of said playing device;
(e) searching for an actual private key corresponding to said private key identification;
(f) decrypting said delivered intermediate key with said actual private key;
(g) obtaining said original media key by decrypting said decrypted intermediate key with said media identification; and
(h) decrypting said delivered media data set with said obtained media key, wherein said media identification and said public key are separately provided and are independent of each other.
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Abstract
A copy protection method and a copy protection system are disclosed. The system includes a private key verifier receiving a media certificate that includes a private key identification of a compliant playing device and searching for an actual private key corresponding to the private key identification, an intermediate key decryptor receiving an encrypted intermediate key and decrypting the intermediate key with the actual private key, a media key decryptor obtaining an original media key by decrypting the decrypted intermediate key with a media identification; and a media data decryptor receiving an encrypted media data set and decrypting the media data set with the original media key. The method and system of the present invention are applicable to all types of digital media data, and it makes no assumption of any specific media properties. The primary goal of the present invention is to significantly reduce the possibility of making any illegal copies on any nonstandard equipment and is to restrict the media data transfers only to authorized entities.
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Citations
18 Claims
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1. A copy protection method for digital media, the method comprising:
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(a) encrypting an original media data set with a symmetric algorithm corresponding to an original media key; (b) generating an intermediate key by encrypting said original media key with a media identification; (c) encrypting said intermediate key with a public key of a compliant playing device; (d) delivering said encrypted media data set, said encrypted intermediate key, and a media certificate to said playing device, said certificate including a private key identification of said playing device; (e) searching for an actual private key corresponding to said private key identification; (f) decrypting said delivered intermediate key with said actual private key; (g) obtaining said original media key by decrypting said decrypted intermediate key with said media identification; and (h) decrypting said delivered media data set with said obtained media key, wherein said media identification and said public key are separately provided and are independent of each other. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A copy protection system for digital media, the system comprising:
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a private key verifier receiving a media certificate that includes a private key identification of a compliant playing device and searching for an actual private key corresponding to said private key identification; an intermediate key decryptor receiving an encrypted intermediate key and decrypting said intermediate key with said actual private key; a media key decryptor obtaining an original media key by decrypting said decrypted intermediate key with a media identification; and a media data decryptor receiving an encrypted media data set and decrypting said media data set with said original media key, wherein said original media key and said intermediate key are encrypted with independent encipherment algorithms. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A copy protection method for digital media, the method comprising:
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(a) receiving an encrypted media data set, an encrypted intermediate key, and a media certificate from an external source, wherein an original media data set is encrypted with an original media key to create the encrypted media data set, said encrypted intermediate key is generated by encrypting an original media key with a media identification and is encrypted by a public key of the receiving device, and said media certificate includes a private key identification of said receiving device, wherein said original media key and said intermediate key are encrypted with independent encipherment algorithms and wherein said media identification and said public key are separately provided and are independent of each other; (b) searching for an actual private key corresponding to said private key identification; (c) decrypting said delivered encrypted intermediate key with said actual private key; (d) obtaining said original media key by decrypting said decrypted intermediate key with said media identification; and (e) decrypting said delivered encrypted media data set with said obtained media key. - View Dependent Claims (15, 16, 17, 18)
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Specification