Encrypting a digital object on a key ID selected therefor

• US 7,016,498 B2
• Filed: 11/05/2004
• Issued: 03/21/2006
• Est. Priority Date: 03/27/1999
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Venkatesan, Ramarathnam, Peinado, Marcus
• Primary Examiner(s): Abdi, Kambiz
• Application Number:
  US10/982,105
• Publication Number:
  US 20050086478A1
• Time in Patent Office: 501 Days
• Field of Search: 380/43, 380/270, 380/273, 380/274, 380/277, 380/201, 713/162, 713/186, 713/168, 713/165, 705/51, 705/57
• US Class Current: 380/277
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G06F 21/71 to assure secure computing or processing of information
• CPC Class Codes: G06F 21/84 output devices, e.g. displays or monitors
• CPC Class Codes: G06F 2211/007 Encryption, En-/decode, En-/decipher, En-/decypher, Scramble, (De-)compress
• CPC Class Codes: G06F 2221/2105 Dual mode as a secondary aspect
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: G06F 2221/2137 Time limited access, e.g. to a computer or data
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: G07F 9/002 Vending machines being part of a centrally controlled network of vending machines
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds

Abstract

To encrypt a digital object, a key ID is selected for the digital object, and a function ƒ( ) having an input and an output is selected. The selected key ID is then employed as the input to the function ƒ( ), and the output of such function ƒ( ) is employed as the key (KD) for the digital object: ƒ(key ID) key (KD). The digital object is then according to such key (KD), and the encrypted digital object is distributed.

Claims

1. A computer-readable medium having computer-executable instructions for encrypting a digital object, the computer-executable instructions performing:

selecting a key ID for the digital object;

selecting a function f( ) having an input and an output;

employing the selected key ID as the input to the function f( );

employing the output of such function f( ) as the key (KD) for the digital object;

f(key ID) key (KD),

encrypting such digital object according to such key (KD); and

distributing such encrypted digital object.

2. The computer-readable medium of claim 1 wherein the computer-executable instructions further perform distributing the key ID along with the encrypted digital object.

3. The computer-readable medium of claim 1 wherein the computer-executable instructions further perform selecting the key ID for the digital object according to a member selected from a group consisting of randomly and serially.

4. The computer-readable medium of claim 1 wherein the computer-executable instructions further perform employing the selected key ID along with a secret seed as the input to the function f( ):

f(key ID, seed) key (KD).

5. The computer-readable medium of claim 4 wherein the seed has a seed ID, and wherein the method comprises employing the selected key ID and the secret seed along with the seed ID as the input to the function f( ):

f(key ID, seed, seed ID) key (KD).

6. The computer-readable medium of claim 1 wherein the computer-executable instructions further perform employing the output of the function f( ) as a symmetric encryption and decryption key (KD) for the digital object.

7. The computer-readable medium of claim 1 wherein the computer-executable instructions further perform selecting a one-way function f( ).

8. The computer-readable medium of claim 7 wherein the computer-executable instructions further perform selecting a one-way function f( ) from a group consisting of a secure hashing algorithm (SHA) or an MD5 algorithm.

9. The computer-readable medium of claim 1 wherein the computer-executable instructions further perform:

receiving a request for the key (KD) from a requester, the request including the key ID;

employing the included key ID as the input to the function f( );

employing the output of such function f( ) as the requested key (KD);

f(key ID) key (KD); and

distributing such key (KD) to the requestor.

10. The computer-readable medium of claim 9 wherein the computer-executable instructions further perform the request for the key (KD) including the key ID as distributed along with the encrypted digital object.

11. The computer-readable medium of claim 9 wherein the computer-executable instructions further perform employing the selected key ID along with a secret seed as the input to the function f( ):

f(key ID, seed) key (KD),

both when producing the key (KD) to encrypt the digital object and when producing the key (KD) to distribute to the requestor.

12. The computer-readable medium of claim 11 wherein the seed has a seed ID, and wherein the method comprises employing the selected key ID and the secret seed along with the seed ID as the input to the function f( ):

f(key ID, seed, seed ID) key (KD),

both when producing the key (KD) to encrypt the digital object and when producing the key (KD) to distribute to the requester.

13. The computer-readable medium of claim 9 wherein the computer-executable instructions further perform employing the output of the function f( ) as a symmetric encryption and decryption key (KD) for the digital object.

14. The computer-readable medium of claim 9 wherein the computer-executable instructions further perform selecting a one-way function f( ).

15. The computer-readable medium of claim 14 wherein the computer-executable instructions further perform selecting a one-way function f( ) from a group consisting of a secure hashing algorithm (SHA) or an MD5 algorithm.

16. The computer-readable medium of claim 9 wherein the computer-executable instructions further perform:

receiving a license request for a digital license including the key (KD) from a license requestor, the license request including the key ID;

approving the license request;

employing the included key ID as the input to the function f( );

employing the output of such function f( ) as the requested key (KD);

f(key ID) key (KD); and

distributing such key (KD) to the license requestor as part of a digital license.

17. The computer-readable medium of claim 16 wherein the computer-executable instructions further perform receiving a license request for a digital license including the key (KD), the license request including the key ID as distributed along with the encrypted digital object.

18. The computer-readable medium of claim 9 wherein the computer-executable instructions further perform providing an authorized key server with the selected function f( ), wherein the request for the key (KD) is received by the key server.

19. The computer-readable medium of claim 18 wherein the computer-executable instructions further perform:

employing the key ID along with a secret seed as the input to the function f( );

f(key ID, seed) key (KD),

when producing the key (KD) to encrypt the digital object;

providing the authorized key server with the selected function f( ) and the secret seed; and

employing, by the key server, the included key ID along with the provided secret seed as the input to the provided function f( );

f(key ID, seed) key (KD),

when producing the key (KD) to distribute to the requestor.

20. The computer-readable medium of claim 19 wherein the secret seed has a seed ID, wherein the computer-executable instructions further perform:

employing the key ID and the secret seed along with the seed ID as the input to the function f( );

f(key ID, seed, seed ID) key (KD),

when producing the key (KD) to encrypt the digital object;

providing the authorized key server with the selected function f( ), the secret seed, and the seed ID thereof;

receiving, by the key server, the request for the key (KD) including the key ID and the seed ID as distributed along with the encrypted digital object;

selecting, by the key server, the secret seed based on the received seed ID; and

employing, by the key server, the included key ID, the included seed ID, and the selected seed as the input to the provided function f( );

f(key ID, seed, seed ID) key (KD),

when producing the key (KD) to distribute to the requestor.

27. The computer system of claim 6 comprising means for selecting a one-way function f( ) from a group consisting of a secure hashing algorithm (SHA) or an MD5 algorithm.

28. The computer system of claim 1 wherein the key is employed to encrypt a digital object, the computer system further comprising:

receiving a request for the key from a requestor to decrypt the encrypted digital object, the request including the key ID;

employing the included key ID as the input to the function f( );

employing the output of such function f( ) as the requested key;

f(key ID) key; and

distributing such requested key to the requestor.

29. The computer system of claim 8 comprising means for employing the selected key ID along with a secret seed as the input to the function f( ):

f(key ID, seed) key,

both when producing the key to encrypt the digital object and when producing the key to distribute to the requestor.

30. The computer system of claim 9 wherein the seed has a seed ID, and wherein the computer system comprises means for employing the selected key ID and the secret seed along with the seed ID as the input to the function f( ):

f(key ID, seed, seed ID) key,

both when producing the key to encrypt the digital object and when producing the key to distribute to the requestor.

31. The computer system of claim 8 comprising means for employing the output of the function f( ) as a symmetric encryption and decryption key.

32. The computer system of claim 8 comprising means for selecting a one-way function f( ).

33. The computer system of claim 12 comprising means for selecting a one-way function f( ) from a group consisting of a secure hashing algorithm (SHA) or an MD5 algorithm.

21. A computer system for producing a security key comprising:

means for selecting a key ID for the key;

means for selecting a function f( ) having an input and an output;

means for employing the selected key ID as the input to the function f( );

means for employing the output of such function f( ) as the key;

f(key ID) key.

22. The computer system of claim 21 comprising means for selecting the key ID for the key according to a member selected from a group consisting of randomly and serially.

23. The computer sytem of claim 22 comprising means for employing the selected key ID along with a secret seed as the input to the function f( ):

f(key ID, seed) key (KD).

24. The computer system of claim 21 wherein the seed has a seed ID, and wherein the computer system comprises means for employing the selected key ID and the secret seed along with the seed ID as the input to the function f( ):

f(key ID, seed, seed ID) key (KD).

25. The computer system of claim 24 comprising means for employing the output of the function f( ) as a symmetric encryption and decryption key.

26. The computer system of claim 21 comprising means for selecting a one-way function f( ).