Systems and methods for client authentication
View Patent ↗A server computer queries a client device using a test fingerprint that does not correspond to any document stored in the client device, and restricts access by the client device to the server computer if the query result is incorrect. In some implementations, the server selects a set of first fingerprints associated with documents stored in the client device, generates a set of test fingerprints, none of which are associated with any document stored in the client device, and queries the client device using fingerprints from the set of first fingerprints and the set of test fingerprints to produce query results. The server computer restricts access by the client device to the server computer if at least one of the query results is incorrect, and enables the client device to access the server computer if at least a predefined number of the query results are correct and none are incorrect.
1. A method, comprising:
at a server computer:
selecting a set of first fingerprints that correspond to documents stored in a client device, wherein the set of first fingerprints includes fingerprints of documents that correspond to entries in a Bloom filter;
generating a set of test fingerprints that do not correspond to any document stored in the client device;
querying the client device using fingerprints from the set of first fingerprints and the set of test fingerprints to produce a set of query results;
restricting access by the client device to the server computer if at least one of the query results is incorrect; and
enabling the client device to access the server computer if at least a predefined number of the query results are correct and none of the query results are incorrect.
2. The method of claim 1 , wherein the test fingerprints are generated using a random or pseudo-random process.
3. The method of claim 1 , wherein at least one of the first fingerprints is a URL fingerprint of a document cached by the client device.
4. The method of claim 1 , wherein the server computer receives a client cache map from the client device in a previous session.
5. The method of claim 1 , wherein restricting access includes invalidating a client cookie.
6. A server computer, comprising:
memory;
at least one processor; and
at least one program stored in the memory and executed by the at least one processor, the at least one program including instructions for:
selecting a set of first fingerprints that correspond to documents stored in a client device, wherein the set of first fingerprints includes fingerprints of documents that correspond to entries in a Bloom filter;
generating a set of test fingerprints that do not correspond to any document stored in the client device;
querying the client device using fingerprints from the set of first fingerprints and the set of test fingerprints to produce a set of query results;
restricting access by the client device to the server computer if at least one of the query results is incorrect; and
enabling the client device to access the server computer if at least a predefined number of the query results are correct and none of the query results are incorrect.
7. The server computer of claim 6 , including instructions for generating the test fingerprints using a random or pseudo-random process.
8. The server computer of claim 6 , wherein at least one of the first fingerprints is a URL fingerprint of a document stored at the client device.
9. The server computer of claim 6 , including instructions for receiving a client cache map from the client device in a previous session.
10. The server computer of claim 6 , wherein the instructions for restricting access include instructions for invalidating a client cookie.
11. A non-transitory computer readable storage medium storing one or more programs configured for execution by one or more processors of a server computer, the one or more programs comprising instructions for:
selecting a set of first fingerprints that correspond to documents stored in a client device, wherein the set of first fingerprints includes fingerprints of documents that correspond to entries in a Bloom filter;
generating a set of test fingerprints that do not correspond to any document stored in the client device;
querying the client device using fingerprints from the set of first fingerprints and the set of test fingerprints to produce a set of query results;
restricting access by the client device to the server computer if at least one of the query results is incorrect; and
enabling the client device to access the server computer if at least a predefined number of the query results are correct and none of the query results are incorrect.
12. The non-transitory computer readable storage medium of claim 11 , including instructions for generating the test fingerprints using a random or pseudo-random process.
13. The non-transitory computer readable storage medium of claim 11 , wherein at least one of the first fingerprints is a URL fingerprint of a document stored at the client device.
14. The non-transitory computer readable storage medium of claim 11 , including instructions for receiving a client cache map from the client device in a previous session.
15. The non-transitory computer readable storage medium of claim 11 , wherein the instructions for restricting access include instructions for invalidating a client cookie.