Patent ID: 8270610
Filing Date: 2012-09-18
Classification: H04L,H04W

Abstract:
1. A wireless communication system, comprising: a first communication apparatus; and a second communication apparatus that transmits/receives encrypted communication data to/from the first communication apparatus by radio, the first communication apparatus comprising: a first encrypting/decrypting unit encrypting the communication data and decrypting the encrypted communication data; a first interface unit electrically connectable with a portable nonvolatile memory, to which the nonvolatile memory can be physically removably inserted; and a first cryptography key processing unit generating a temporary cryptography key used for encrypting/decrypting the communication data and a master cryptography key for generating the temporary cryptography key, and the second communication apparatus comprising: a second encrypting/decrypting unit encrypting the communication data and decrypting the encrypted communication data; a second interface unit electrically connectable with the nonvolatile memory, to which the nonvolatile memory storing the master cryptography key is physically removably inserted; and a second cryptography key processing unit generating the temporary cryptography key based on the master cryptography key read from the nonvolatile memory connected with the second interface unit, wherein the first communication apparatus includes a first cryptography key storage unit storing the master cryptography key and the temporary cryptography key, the second communication apparatus includes a second cryptography key storage unit storing the master cryptography key and the temporary cryptography key, the first cryptography key storage unit stores identification (ID) information of the second communication apparatus and the master cryptography key in association with each other, and the second cryptography key storage unit stores ID information of the first communication apparatus, ID information of the second communication apparatus, and the master cryptography key in association with one another, the second communication apparatus is able to write ID information of the first communication apparatus and ID information of the second communication apparatus held in the second cryptography key storage unit to the nonvolatile memory connected with the second interface unit, and upon ID information of the second communication apparatus generated by the first communication apparatus being stored in the nonvolatile memory connected with the first interface unit, the first communication apparatus generates the master cryptography key corresponding to ID information of the second communication apparatus stored in the nonvolatile memory without generating new ID information, and stores the generated master cryptography key in the first cryptography key storage unit, and upon ID information of the second communication apparatus generated by the first communication apparatus not being stored in the nonvolatile memory connected with the first interface unit, the first communication apparatus generates new ID information assigned to the second communication apparatus and the master cryptography key corresponding to the new ID information to store the new ID information and the master cryptography key in the first cryptography key storage unit.