Patent ID: 6711264
Filing Date: 2004-03-23
Classification: H04L

Abstract:
A security method of ensuring privacy and security in a communication system where communication devices are configured to conduct simultaneous two-way communication via a single network, said security method comprising:storing a plurality of encryption keys and corresponding key identifications in each communication device; obtaining from one of the communication devices predetermined user information when a communication device participates in the network and storing the user information including at least a list of the other communication devices that participate in the network in the participating communication device; selecting a communication device from the other communication devices in the stored list, requesting from the selected communication device the stored encryption key of the selected communication device, and storing the requested encryption key sent from the selected communication device in response to the requesting; distributing a stored encryption key to a requesting communication device, upon receiving a request for the stored encryption key from the requesting communication device to the requesting communication device; receiving communication contents from at least one of the communication devices and encrypting the communication contents using one of the stored encryption keys, and transmitting to one of the other communication devices via the network the encrypted communication contents along with the corresponding key identification identifying one of the stored encryption keys used to encrypt the communication contents; and receiving encrypted communication contents and a key identification from at least one of the communication devices and decrypting the communication contents by examining whether an encryption key identified by the key identification is previously stored, and requesting the encryption key from one of the communication devices by specifying the identification key, if the encryption key is not previously stored.