Encryption communication method and system

An encryption communication system for establishing encryption communication to be performed by a first terminal and a second terminal through first and second session management servers, comprising:

• a key generation information management server for selecting an encryption algorithm suite to be used for the encryption communication established between the first terminal and the second terminal ,
• wherein the first session management server includes:
• a function acquiring a first key generation information which is composed of a plurality of set items needed to determine a set value for generating a session key to be used by its own terminal from the first terminal, and stores a set value candidate for each set item;
• and
• a function to send the first key generation information to the key generation information management server,
• wherein the second session management server includes:
• a function acquiring a second key generation information which is composed of a plurality of set items needed to determine a set value for generating a session key to be used by its own terminal from the second terminal, and stores a set value candidate for each set item;
• and
• a function to send the second key generation information to the key generation information management server, and
• wherein the key generation information management server includes:
• a key generation information receiving function to receive the first key generation information from the first session management server, and to receive the second key generation information from the second session management server;
• a key generation information register function to register the first and second key generation information received;
• and
• a function to select the algorithm suite to be used in the encryption communication, on the basis of the first key generation information and the second key generation information received, in accordance with a predetermined policy, when a communication starting request is received from the first terminal to the second terminal, by the first session management server.