Patent ID: 8825738

Claim:
A method of operating a server for providing a network service, said method comprising: receiving a first hash value F(Pa′, Pb) from an information terminal of a user B having a first database containing personal information Pa′ of a user A and personal information Pb of said user B, said first hash value being generated by a hash function applied to a connection of said personal information Pa′ and said personal information Pb; correlating an identification tag of said user B with said first hash value F(Pa′, Pb), said identification tag of said user B uniquely identifying said user B in said network service, and memorize said identification tag of said user B and said first hash value F(Pa′, Pb); receiving a second hash value F(Pa, Pb′) from an information terminal of said user A having a second database containing personal information Pa of said user A and personal information Pb′ of said user B, said second hash value being generated by a hash function applied to a connection of said personal information Pa and said personal information Pb′, and searching for a hash value which is equal to said second hash value F(Pa, Pb′) and detect said identification tag of said user B by detecting said first hash value F(Pa′, Pb), which is equal to and said second hash value F(Pa′, Pb), and sending said identification tag of said user B to said information terminal of said user A on a detection of said first hash value F(Pa′, Pb), which is equal to said second hash value F(Pa, Pb′).