Patent ID: 8612758

Claim:
A method for secure identification of a server station and a client station that are both connected and interact over data communications networks during a transaction, said server station and said client station each comprising respectively a database and a data processor, a code sequence being contained in both databases of said server station and said client station, the method comprising the sequential steps of: a) transmitting on the part of the server station to the client station, an identification index of a reference cell that belongs to said code sequence and a first code that belongs to said code sequence and is chosen according to a first criterion, which is known to both said server station and said client station and is based on said identification index; b) marking, after step a) on the part of said server station, the identification index that has been used as unusable for subsequent transactions; c) identifying, on the part of said client station, said reference cell in the sequence of codes through said identification index and calculating the first code that is expected to have been received from said server station according to the common first criterion and the identification index; d) verifying, after said step c), on the part of said client station that said first code received from the server station is equal to the calculated first code; e) if the first code calculated in the client station is equal to the first code sent by the server station, e1) marking on said client station, the index cell as an already used cell; and e2) after said marking on said client station the process continues transmitting, on the part of said client station toward said server station, a second code, which belongs to said code sequence and is calculated according to a second criterion, which is known both to said server station and to said client station and is also based on the identification index; and f) verifying said second code on the part of the server station.