Data repository and method for promoting network storage of data

• US 7,457,959 B2
• Filed: 01/07/2004
• Issued: 11/25/2008
• Est. Priority Date: 02/18/2000
• Status: Expired due to Fees

• Current Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Original Assignee: Burnside Acquisition, LLC
• Inventors: Margolus, Norman H., Knight, Thomas F. Jr.
• Primary Examiner(s): Vu; Kimyen
• Assistant Examiner(s): To; Baotran N
• Application Number:
  US10/752,983
• Publication Number:
  US 20040143745A1
• Time in Patent Office: 1,784 Days
• Field of Search: 707/204, 707/2, 707/100, 707/9, 707/10, 713176-181, 713/165, 713/155, 713/178, 713/186, 713/193, 726/4, 380/46
• US Class Current: 713/176
• CPC Class Codes: G06F 16/137 Hash-based content-based indexing of textual data G06F16/31
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 21/60 Protecting data
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 21/6272 by registering files or documents with a third party
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 21/645 using a third party
• CPC Class Codes: Y10S 707/959 Network
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

In general, the invention features methods by which more than one client program connected to a network stores the same data item on a storage device of a data repository connected to the network. In one aspect, the method comprises encrypting the data item using a key derived from the content of the data item, determining a digital fingerprint of the data item, and storing the data item on the storage device at a location or locations associated with the digital fingerprint. In a second aspect, the method comprises determining a digital fingerprint of the data item, testing for whether the data item is already stored in the repository by comparing the digital fingerprint of the data item to the digital fingerprints of data items already in storage in the repository, and challenging a client that is attempting to deposit a data item already stored in the repository, to ascertain that the client has the full data item.

Claims

1. A method for archiving digital records which allows the existence and content of a stored record at a point in time to be proven, while supporting a deletion mechanism which, if applied to the stored record, does not allow its existence to be proven even if the content of the stored record is guessed correctly, the method comprising:

for each record in a set of records;

determining a content fingerprint based on content of the each record;

choosing a number that is distinct from the content fingerprint;

determining a record identifier for the each record based at least in part on the number; and

storing the each record and the number;

selecting a plurality of records from the set of records;

constructing a cryptographic hash for each record of the plurality, based at least in part on both the content fingerprint of the each record and on the record identifier for the each record;

storing a timestamp record that comprises the cryptographic hashes constructed for each record of the plurality;

determining a content fingerprint from the contents of the timestamp record;

recording the content fingerprint for the timestamp record in a manner that allows both the time of the recording and the value of the content fingerprint at the time of the recording to be later proven; and

deleting from storage a one of the plurality of records and also deleting from storage the number of the one record deleted;

wherein the choosing of a number is done in a manner designed to make it impracticable to reconstruct or guess the number if the number has been deleted from storage.

2. The method of claim 1 wherein the number of the one record is a version number.

3. The method of claim 1 wherein the location or locations at which each record in the set of records is stored is determined, at least in part, by the content fingerprint of the each record.

4. The method of claim 1 wherein the content fingerprint is based on a cryptographic hash of at least a portion of the content of the each record.

5. The method of claim 1 wherein the plurality of the set of records comprises records stored during some interval of time.

6. The method of claim 1 wherein the recording step comprises publishing the content fingerprint for the timestamp record in a newspaper or communicating the content fingerprint for the timestamp record to a digital timestamping service.

7. The method of claim 1 wherein a first one of the plurality of records has the same content as a second one of the plurality of records and the second one of the plurality of records is associated with the same storage space as the first one.

8. The method of claim 1 wherein both the plurality of records and the numbers of the records in the plurality are stored in a disk-based data storage system.

9. The method of claim 1 wherein the records of the set of records are object versions in a data repository which uses content fingerprints to name blocks of data in order to reduce bandwidth or storage space needs.

10. The method of claim 1 wherein the number chosen is pseudorandom.