Patent ID: 8874536

Claim:
A method of identifying the presence of matching information items in a network, the method comprising: using a hashing scheme to generate a set of first hash values from a respective set of first information items stored at a first node; transmitting the set of first hash values from the first node over the network to a second node effective to cause the second node to: compare the set of first hash values at the second node with a set of second hash values generated, using the hashing scheme, from a respective set of second information items stored in the network, to thereby determine at least one matching hash value between the set of first hash values and the set of second hash values; and use the determined at least one matching hash value to identify the presence of at least one matching information item between the set of first information items and the set of second information items; and wherein the hashing scheme is chosen so that each hash value is unique with respect to the other hash values and any particular hash value in the hashing scheme indicates at least ten information items to prevent the particular hash value being used as an identifier of a unique information item, such that the transmission of the set of first hash values to the second node does not disclose the set of first information items to the second node.