Secure peer-to-peer cache sharing

• US 20080082648A1
• Filed: 09/29/2006
• Published: 04/03/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Simon, Daniel R., Ahmed, Khaja E.
• Granted Patent: US 7,617,322 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: H04L 63/126 the source of the received data
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04L 67/1068 Discovery involving direct consultation or announcement among potential requesting and potential source peers
• CPC Class Codes: H04L 67/1091 Interfacing with client-server systems or between P2P systems
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

A system, apparatus, method, and computer-readable medium are provided for secure P2P caching. In one method, a requesting peer obtains a hash of requested data from a server. The requesting peer then transmits a request for the data to other peers. The request proves that the requesting peer has the hash. If a caching peer has the data, it generates a reply to the request that proves that it has the requested data. If the requesting peer receives a reply from a caching peer, the requesting peer establishes a connection to the caching peer and retrieves the data from the caching peer. If the requesting peer does not receive a reply to the request from any other peer, the requesting peer establishes a connection to the server and retrieves the data from the server. The requesting peer stores the data for use in responding to requests from other peers.

Claims

1. A method for securely retrieving data cached in a peer-to-peer network comprising two or more networked peer computers, the method comprising:

transmitting a broadcast request for the requested data on the network, the broadcast request comprising data sufficient to prove possession of a hash value for the requested data to the peer computers;

receiving a reply to the broadcast request from a caching peer computer, the reply comprising data sufficient to prove possession of the requested data by the caching peer computer; and

in response to receiving the reply, receiving the requested data from the caching peer computer.

2. The method of claim 1, further comprising prior to transmitting the broadcast request:

transmitting a request to a server computer for the hash value for the requested data; and

receiving the hash value for the requested data from the server computer.

3. The method of claim 1, wherein the data of the broadcast request comprises a hash of the hash value for the requested data, random data generated by a requesting peer computer, a timestamp, an identifier for the requesting peer computer, and a hash of the hash value for the requested data concatenated with the random data generated by the requesting peer, the timestamp, and the identifier for the requesting peer computer.

4. The method of claim 1, wherein the data of the reply comprises random data generated by the caching peer computer, a hash of the hash value for the requested data, and a hash of the hash value for the requested data concatenated with the random data generated by the caching peer computer, the identifier for the requesting peer computer, an identifier for the caching peer computer, and the timestamp.

5. The method of claim 2, further comprising retrieving the requested data from the server computer in response to failing to receive a reply to the broadcast request from any of the peer computers.

6. The method of claim 5, further comprising in response to retrieving the requested data from the caching peer computer:

storing the requested data; and

indexing the stored requested data using a hash of the hash value for the requested data concatenated with a string.

7. The method of claim 6, wherein receiving the requested data from the caching peer computer comprises:

establishing a secure network connection to the caching peer computer; and

receiving the requested data from the caching peer computer over the secure network connection.

8. A computer-readable medium having computer-executable instructions stored thereon which, when executed by a computer, will cause the computer to perform the method of claim 1.

9. A computer-controlled apparatus operative to perform the method of claim 1.

10. A method for securely providing data cached in a peer-to-peer network comprising two or more networked peer computers, the method comprising:

receiving a broadcast request for the requested data at a caching peer computer, the broadcast request comprising data sufficient to prove possession of a hash value for the requested data by the requesting peer computer;

in response to receiving the broadcast request, determining whether the caching peer computer has the requested data;

in response to determining that the caching peer computer has the requested data, transmitting a reply to the broadcast request, the reply comprising data sufficient to prove possession of the requested data by the caching peer computer; and

transmitting the requested data to the requesting peer computer.

11. The method of claim 10, wherein the data of the broadcast request comprises a hash of the hash value for the requested data, random data generated by a requesting peer computer, a timestamp, an identifier for the requesting peer computer, and a hash of the hash value for the requested data concatenated with the random data generated by the requesting peer, the timestamp, and the identifier for the requesting peer.

12. The method of claim 11, wherein determining whether the caching peer computer has the requested data comprises:

searching an index stored at the caching peer computer for the hash of the hash value for the requested data; and

in response to locating the hash of the hash value for the requested data in the index, determining that the caching computer has the requested data.

13. The method of claim 12, wherein the data of the reply comprises random data generated by the caching peer computer, a hash of the hash value for the requested data, and a hash of the hash value for the requested data concatenated with the random data generated by the caching peer computer, the identifier for the requesting peer computer, an identifier for the caching peer computer, and the timestamp.

14. The method of claim 13, wherein transmitting the requested data to the requesting peer computer comprises:

establishing a secure network connection with the requesting peer computer; and

transmitting the requested data to the requesting peer computer over the secure network connection.

15. A computer-readable medium having computer-executable instructions stored thereon which, when executed by a computer, will cause the computer to perform the method of claim 10.

16. A method for caching data in a peer-to-peer network comprising two or more networked peer computers, the method comprising:

providing a cache manager for execution at each of the peer computers, the cache manager operative to receive a request for data from an application protocol, transmit a broadcast request comprising data sufficient to prove possession of a hash value for the requested data to the peer computers, receive a reply to the broadcast request comprising data sufficient to prove possession of the requested data by a caching peer computer, and to receive the requested data from the caching peer computer in response to receiving the reply.

17. The method of claim 16, wherein the cache manager executes in conjunction with a networking protocol stack on the peer computers.

18. The method of claim 17, wherein the cache manager is further operative to store the received requested data for use in responding to requests for the data.

19. The method of claim 18, wherein the cache manager is further operative to:

receive a broadcast request comprising data sufficient to prove possession of a hash of the requested data by a requesting peer computer, to determine whether a caching peer computer has the requested data in response to receiving the broadcast request, to transmit a reply to the broadcast request comprising data sufficient to prove possession of the requested data by the caching peer computer, and to transmit the requested data to the requesting peer computer.

20. A computer-readable medium having computer-executable instructions stored thereon which, when executed by a computer, will cause the computer to perform the method of claim 16.