Patent ID: 7984494

Claim:
A computer system, comprising: a first computer including a first processor, a first memory, and a first interface; a plurality of second computers each including a second processor, a second memory, and a second interface; and a load balancer configured to balance loads of the plurality of second computers, wherein: each of the second computers is configured to directly establish a security association with the first computer, the load balancer is further configured to transfer a packet received from the first computer to one of the plurality of second computers; the second memory of each of the second computers is configured to store a set of inbound SA candidate information designating an inbound safe communication path, in which address information of a destination remains unknown, and outbound SA candidate information designating an outbound safe communication path, in which address information of a source remains unknown; the second processor of one of the second computers is configured to decrypt a packet encrypted by the first computer by using the stored inbound SA candidate information or inbound SA candidate information stored in a different one of the second computers upon reception of the encrypted packet or inbound SA candidate information stored in a different one of the second computers; and the second processor of the one of the second computers is further configured to create a set of inbound SA information outbound SA information, by designating the address information of the destination of the inbound safe communication path and the address information of the source of the outbound safe communication path based on the set of the inbound SA candidate information and the outbound SA candidate information and destination address information of the encrypted packet, and to store the created set of the inbound SA information and the outbound SA information on the second memory for successive safe communications with the first processor, upon successful decryption of the encrypted packet.