Metering retrieval of encrypted data stored in customer data retrieval terminal

Claims

I claim:

1. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal;

(d) recording the amount of data retrieved from said file;

(e) reporting the recorded amount of data retrieved from said file; and

(f) authenticating said report.

2. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal; and

(d) recording the amount of data retrieved from said file;

wherein step (b) comprises the step of

(e) authenticating said credit signal.

3. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal;

(d) recording the amount of data retrieved from said file; and

(e) determining whether credit should be extended in response to a retrieval request prior to providing said encryption key, and, if so, the amount of said credit to be indicated by said credit signal.

4. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal; and

(d) recording the amount of data retrieved from said file;

wherein

step (a) comprises providing a memory containing encrypted data files for each of a plurality of different data vendors, with a different said encryption key and credit signal being required to retrieve the data file and/or files associated with each of said vendors;

step (b) comprises providing a separate set of encryption key and credit signal for each vendor associated with a said file retrieval authorization;

step (c) comprises limiting retrieval of files associated with different vendors separately in accordance with the encryption key and credit signal provided for said vendor; and

step (d) comprises separately recording the amount of retrieved data with respect to each vendor.

5. A method according to claim 4, wherein

step (a) comprises providing a memory containing a plurality of encrypted data files for a given data vendor; and

step (d) comprises separately recording the amount of retrieved data with respect to each data file of said given vendor.

6. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal; and

(d) recording the amount of data retrieved from said file; wherein

step (a) comprises providing a said memory that further contains unencrypted initialization vector data uniquely associated with different blocks of data within the encrypted data file; and

the method further comprises the steps of

(e) using said initialization vector data in combination with said encryption key to retrieve data from said file; and

(f) using said unique initialization vector data upon said retrieval to record the identity of the block of data retrieved from said file.

7. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal; and

(d) recording the amount of data retrieved from said file; wherein

step (a) comprises providing a said memory that further contains cost data associated with different blocks of data that can be retrieved from said memory; and

the method further comprises the steps of

(e) processing the cost data with said credit signal in response to a request to retrieve a given block of data to determine whether retrieval of said requested block of data is authorized; and

(f) authenticating said cost data prior to said processing of same.

8. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal; and

(d) recording the amount of data retrieved from said file; wherein

step (a) comprises providing said memory in a customer data retrieval terminal; and

step (b) comprises determining in an authorization center located remotely from said customer terminal whether the status of an account associated with said customer terminal warrants authorizing said retrieval, and, if so, providing said encryption key and said credit signal in the customer data retrieval terminal.

9. A method according to claim 8, wherein

step (a) comprises providing a said memory that further contains cost data associated with different blocks of data that can be retrieved from said memory; and

the method further comprises the steps of

(e) recording in said customer terminal, the cost data for the blocks of data retrieved in relation to said credit signal provided therein; and

(f) reporting to the authorization center the record of said cost data in relation to said credit signal.

10. A method according to claim 9, further comprising the step of

(g) authenticating said report of the record of said cost data in relation to said credit signal.

11. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing in the customer data retrieval terminal a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval in response to a request to retrieve data from said file in said customer data retrieval terminal by determining in an authorization center located remotely from the customer terminal whether the status of an account associated with said customer terminal warrants authorizing said retrieval, and, if so, providing to the customer terminal an encryption key for enabling retrieval of data from said file in the customer data retrieval terminal; and

(c) recording the retrieval of data from said file by said customer retrieval terminal and debiting said account for said retrieval.

12. A method according to claim 11 wherein step (b) comprises the step of

(d) encrypting said encryption key.

13. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing in the customer data retrieval terminal a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval in response to a request to retrieve data from said file in said customer data retrieval terminal by determining in an authorization center located remotely from the customer terminal whether the status of an account associated with said customer terminal warrants authorizing said retrieval, and, if so, providing to the customer terminal an encryption key for enabling retrieval of data from said file;

(c) recording the retrieval of data from said file by said customer retrieval terminal and debiting said account for said retrieval; and

(d) verifying decryption of data from said requested file pursuant to use of said encryption key prior to debiting said account.

14. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal;

means for recording the amount of data retrieved from said file;

means for reporting the recorded amount of data retrieved from said file; and

means for authenticating said report.

15. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comrpising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal; and

means for recording the amount of data retrieved from said file;

wherein the authorization means comprises

means for authenticating said credit signal.

16. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal;

means for recording the amount of data retrieved from said file; and

means for determining whether credit should be extended in response to a retrieval request prior to providing said encryption key, and, if so, the amount of said credit to be indicated by said credit signal.

17. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal; and

means for recording the amount of data retrieved from said file; wherein

said memory contains encrypted data files for each of a plurality of different data vendors, with a different said encryption key and credit signal being required to retrieve the data file and/or files associated with each of said vendors;

the authorization means comprises means for providing a separate set of encryption key and credit signal for each vendor associated with a said file retrieval authorization;

the limiting means comprises means for limiting retrieval of files associated with different vendors separately in accordance with the encryption key and credit signal provided for said vendor; and

the recording means comprises means for separately recording the amount of retrieved data with respect to each vendor.

18. A system according to claim 17 wherein

the memory contains a plurality of encrypted data files for a given data vendor; and

the recording means comprises means for separately recording the amount of retrieved data with respect to each data file of said given vendor.

19. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal; and

means for recording the amount of data retrieved from said file;

wherein

the memory further contains unencrypted initialization vector data uniquely associated with different blocks of data within the encrypted data file; and

the system further comprises

means for using said initialization vector data in combination with said encryption key to retrieve data from said file; and

means for using said unique initialization vector data upon said retrieval to record the identity of the block of data retrieved from said file.

20. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal; and

means for recording the amount of data retrieved from said file;

wherein

the memory further contains cost data associated with different blocks of data that can be retrieved from said memory; and

the system further comprises

means for processing the cost data with said credit signal in response to a request to retrieve a given block of data to determine whether retrieval of said requested block of data is authorized; and

means for authenticating said cost data prior to said processing of same.

21. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal; and

means for recording the amount of data retrieved from said file;

wherein

the memory is in a customer data retrieval terminal; and

the authorization means comprises means for determining in an authorization center located remotely from said customer terminal whether the status of an account associated with said customer terminal warrants authorizing said retrieval, and, if so, providing said encryption key and said credit signal in the customer data retrieval terminal.

22. A system according to claim 21, wherein

the memory further contains cost data associated with different blocks of data that can be retrieved from said memory; and

the system further comprises

means for recording in said customer terminal, the cost data for the blocks of data retrieved in relation to said credit signal provided therein; and

means for reporting to the authorization center the record of said cost data in relation to said credit signal.

23. A system according to claim 22, further comprising

means for authenticating said report of the record of said cost data in relation to said credit signal.

24. A system for controlling and accounting for retrieval of data from a memory in the customer data retrieval terminal, wherein the memory contains an encrypted data file from which retrieval must be authorized, the system comprising

means for authorizing said retrieval in response to a request to retrieve data from said file in said customer data retrieval terminal by determining in an authorization center located remotely from the customer terminal whether the status of an account associated with said customer terminal warrants authorizing said retrieval, and, if so, providing to the customer terminal an encryption key for enabling retrieval of data from said file in the customer data retrieval terminal; and

means for recording the retrieval of data from said file by said customer retrieval terminal and debiting said account for said retrieval.

25. A system according to claim 24, wherein

the authorizing means comprise means for encrypting said encryption key.

26. A system according to claim 24, wherein the memory is a compact disc ROM.

27. A system for controlling and accounting for retrieval of data from a memory in the customer data retrieval terminal, wherein the memory contains an encrypted data file from which retrieval must be authorized, the system comprising

means for authorizing said retrieval in response to a request to retrieve data from said file in said customer data retrieval terminal by determining in an authorization center located remotely from the customer terminal whether the status of an account associated with said customer terminal warrants authorizing said retrieval, and, if so, providing to the customer terminal an encryption key for enabling retrieval of data from said file;

means for recording the retrieval of data from said file by said customer retrieval terminal and debiting said account for said retrieval; and

means for verifying decryption of data from said requested file pursuant to use of said encryption key prior to debiting said account.

28. A method of controlling and accounting for retrieval of data from a memory, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

(c) limiting the amount of data retrieved from said file in accordance with said credit signal; and

(d) recording the amount of data retrieved from said file.

29. A method according to claim 28, wherein step (b) comprises the step of

(e) encrypting said encryption key.

30. A method according to claim 28, wherein

step (a) comprises providing a memory containing a plurality of encrypted data files for a given data vendor; and

step (d) comprises separately recording the amount of retrieved data with respect to each data file of said given vendor.

31. A method according to claim 28, wherein

step (a) comprises providing a said memory that further contains unencrypted initialization vector data associated with the encrypted data file; and

the method further comprises the step of

(e) using said initialization vector data in combination with said encryption key to retrieve data from said file.

32. A method according to claim 28, wherein

step (a) comprises providing a said memory that further contains unencrypted identification data uniquely associated with different blocks of data within the encrypted data file; and

the method further comprises the step of

(e) using said unique identification data upon said retrieval to record the identity of the block of data retrieved from said file.

33. A method according to claim 28, wherein

step (a) comprises providing a said memory that further contains cost data associated with different blocks of data that can be retrieved from said memory; and

the method further comprises the steps of

(e) processing the cost data with said credit signal in response to a request to retrieve a given said block of data to determine whether retrieval of said requested block of data is authorized.

34. A method of controlling and accounting for retrieval of data from a plurality of identical memories by a corresponding plurality of different data retrieval terminals, comprising the steps of

(a) providing a memory containing an encrypted data file from which retrieval must be authorized;

(b) providing a different unit key in each of the retrieval terminals;

(c) authorizing said retrieval by providing an encryption key encrypted in the unit key of the given retrieval terminal for enabling retrieval of said data in the given retrieval terminal and by providing a credit signal addressed to the given retrieval terminal for use in limiting the amount of data to be retrieved from said file by the given retrieval terminal;

(d) limiting the amount of data retrieved from said file in the given retrieval terminal in accordance with said credit signal; and

(e) recording the amount of data retrieved from said file in said retrieval terminal.

35. A system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized, comprising

means for authorizing said retrieval by providing an encryption key for enabling retrieval of said data and a credit signal for use in limiting the amount of data to be retrieved from said file;

means for limiting the amount of data retrieved from said file in accordance with said credit signal; and

means for recording the amount of data retrieved from said file.

36. A system according to claim 35, wherein the authorization means comprises

means for encrypting said encryption key.

37. A system according to claim 35, wherein

the memory contains a plurality of encrypted data files for a given data vendor; and

the recording means comprises means for separately recording the amount of retrieved data with respect to each data file of said given vendor.

38. A system according to claim 35, wherein

the memory further contains unencrypted initialization vector data associated with the encrypted data file; and

the system further comprises

means for using said initialization vector data in combination with said encryption key to retrieve data from said file.

39. A system according to claim 35, wherein

the memory further contains unencrypted identification data uniquely associated with different blocks of data within the encrypted data file; and

the system further comprises

means for using said unique identification data upon said retrieval to record the identity of the block of data retrieved from said file.

40. A system according to claim 35, wherein

the memory further contains cost data associated with different blocks of data that can be retrieved from said memory; and

the system further comprises

means for processing the cost data with said credit signal in response to a request to retrieve a given said block of data to determine whether retrieval of said requested block of data is authorized.

41. A system according to claim 35, wherein the memory is a compact disc ROM.

42. A system for controlling and accounting for retrieval of data from a plurality of identical memories by a corresponding plurality of different data retrieval terminals, wherein each memory contains an encrypted data file from which retrieval must be authorized, the system comprising

means providing a different unit key in key in each of the retrieval terminals;

means for authorizing said retrieval by providing an encryption key encryption in the unit key of the given retrieval terminal for enabling retrieval of said data in the given retrieval terminal and by providing a credit signal addressed to the given retrieval terminal for use in limiting the amount of data to be retrieved from said file by the given retrieval terminal;

means for limiting the amount of data retrieved from said file in the given retrieval terminal in accordance with said credit signal; and

means for recording the amount of data retrieved from said file in said retrieval terminal.

43. A system according to claim 42, wherein the memory is a compact disc ROM.

BACKGROUND OF THE INVENTION

The present invention generally pertains to data retrieval and is particularly directed to limiting and accounting for the retrieval of data from encrypted data files.

SUMMARY OF THE INVENTION

The present invention is a method and system for controlling and accounting for retrieval of data from a memory containing an encrypted data file from which retrieval must be authorized. The system includes means for authorizing such retrieval by providing an encryption key for enabling retrieval of the data and a credit signal for use in limiting the amount of data to be retrieved from the file; means for limiting the amount of data retrieved from the file in accordance with the credit signal; and means for recording the amount of data retrieved from the file. The sytem may further include means for reporting the recorded amount of data retrieved from the file; and means for authenticating such report.

The present invention is particularly suited for retrieving data files stored in a compact disc read-only-memory (CD-ROM).

Additional features of the invention are discussed in relation to the description of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram illustrating the signals communicated between an authorization and key distribution terminal and a customer data retrieval terminal in a preferred embodiment of the present invention.

FIG. 2 is a functional block diagram of the customer data retrieval terminal in the embodiment of FIG. 1.

FIG. 3 is a flow diagram showing operational routines in an alternative preferred embodiment of the present invention.

FIG. 4 is a flow diagram showing operational routines in another alternative preferred embodiment of the present invention.

FIG. 5 is a flow diagram showing certain aspects of the operational routines in still another alternative preferred embodiment of the present invention.

FIG. 6 is a block diagram illustrating the use of a customer data retrieval terminal in a personal computer for retrieving data from a CD-ROM.

FIG. 7 illustrates an exemplary scheme of tiering the retrieval of different types of data fields from a memory in accordance with a preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The use of a preferred embodiment of the system of the present invention is generally described with reference to FIG. 1. The system essentially includes an authorization and key distribution terminal 10 and a customer data retrieval terminal 11; it being understood that in practice there are a plurality of customer data retrieval terminals 11 that communicate with a single authorization and key distribution terminal 10. A memory containing an encrypted data file from which retrieval must be authorized is loaded in the customer data retrieval terminal 11. Different data files in the memory may be associated with different data vendors. Typically, communications between the authorization and key distribution terminal 10 and the customer data retrieval terminal 11 are transmitted over telephone lines.

In order to gain authorization to retrieve encrypted data from a given file stored in the memory loaded in the customer data retrieval terminal 11, the customer causes a file use request signal 12 to be communicated to the authorization and key distribution terminal 10. The file use request signal identifies the file for which retrieval authorization is requested and also contains an ID number identifying the customer terminal 11 from which the request signal 12 is sent.

The authorization and key distribution terminal 10 processes the request signal to determine whether the customer terminal 11 identified by the ID number contained in the file use request signal 12 is authorized to retrieve data from the file identified in the file use request signal 12. Such determination includes checking on the status of a customer account associated with the customer terminal 11 from which the request signal 12 is received; and may further include determining the eligibility of the customer to retrieve data from such file notwithstanding the outcome of the credit check.

Upon determining that the status of the customer account associated with the customer terminal 11 warrants authorizing retrieval of data from the file identified in the file use request signal 12, the authorization terminal 10 authorizes the customer terminal 11 to retrieve data from said file by providing to the customer terminal 11 both and encrypted file key 13 and an authenticated credit data signal 14. The credit data signal 14 indicates an amount of credit to be extended to the customer terminal 11 for retrieval of data from the file identified in the file use request signal 12.

The file key 13 is encrypted in a unit key that is unique to the customer terminal 11 to which the encrypted file key 13 and the authenticated credit signal 14 are being communicated. Unit keys for each of the customer terminals 11 associated with a given authorization and key distribution terminal 10 are stored in the authorization and key distribution terminal 10 and are individually retrieved in accordance with the customer terminal ID number that is included in the file use request signal 12. Each customer data retrieval terminal also permanently stores it own unique unit key. The authenticated credit data signal 14 is generated by including both unencrypted credit data and encrypted credit data that is formed by encrypting the unencrypted credit data with the unit key of the customer terminal that is being authorized.

The operation of the customer data retrieval terminal 11 in retrieving the encrypted data from the memory loaded therein is described with reference to FIG. 2. Certain functional units of the customer data retrieval terminal 11 are implemented in a microcomputer. These functional units include a data decryption unit 16, a file key decryption unit 17, a cost data authentication unit 18, a credit data authentication unit 19, an authenticated credit and debit status report generation unit 20, an authenticated usage report generation unit 21, a retrieval control unit 22 associated with each data vendor, a use history storage unit 23 associated with each data vendor, a unit key memory 24 and a random access memory (RAM) 25. The retrieval control unit 22 includes a credit register 27, a debit register 28, an accumulator 29, a comparator 30 and a logic unit 31. The customer data retrieval terminal 11 further includes a keyboard 33 for generating a file use request 34 and a file access command 35.

A read only memory (ROM) 37 containing the encrypted data files is loaded in the customer data retrieval terminal 11. The ROM 37 includes a plurality of encrypted data files, File A, File B. Each data file includes encryted data blocks, Block 1, Block 2, . . . Block 5. Each data file includes blocks of data of a given type of association. The different data files may be associated with different data vendors and there may be a plurality of data files associated with each of the different vendors. Each block of data includes encrypted data, a block ID (identification) signal, and authenticated cost data. The authenticated cost data indicates the cost associated with retrieving the given encrypted block of data.

To enable the customer data retrieval terminal 11 to retrieve data from any given file in the ROM 37, the file use request 34 identifying a given file is generated by use of the keyboard 33 and combined with the unit ID number 39 for the customer terminal 11 to provide the file use request signal 12 that is communicated to the authorization and key distribution terminal 10. As discussed above, the authorization and key distribution terminal 10 responds to the file use request signal 12 by providing the encrypted file key 13 and the authenticated credit data signal 14 to the customer terminal 11 when the authorization and key distribution terminal determines that the customer terminal 11 is authorized to retrieve the data identified in the file use request signal 12.

The encrypted file key 13 is stored in the RAM 25.

The received credit data signal 14 containing the credit data in both encrypted and unencrypted form is authenticated by the credit data authentication unit 19, which is keyed by the unit key 42 stored in the unit key memory 24 to decrypt the encrypted credit data and thereby provide a decrypted credit data signal, which is compared with the unencrypted credit data signal in the authenticated credit data signal 14 to authenticate the received credit data signal 14. An authenticated credit data signal 41 is stored in the credit register 27 of the retrieval control unit 22 associated with the same vendor as the file from which data retrieval is being authorized. If the credit register 27 already has a credit balance, such balance is incremented by the amount indicated by the authenticated credit signal 41.

A message (not shown) indicating that authorization has been granted for the customer terminal 11 to retrieve data from the requested file is also communicated by the authorization and key distribution center 10 to the customer terminal 11 and displayed on a monitor (not shown) at the customer terminal 11.

To retrieve a given block of data from an authorized data file in the ROM 37, the keyboard 33 is operated to provide a file access command 35 which includes an address signal 44 directed to the ROM 37 for accessing the given block of data. In the example shown in FIG. 1, the accessed block of data is block 5 of file B.