Patent ID: 9553719
Date: 2017-01-24
CPC Classifications: H04L

Claim:
1. A transmitting terminal apparatus transmitting an encryption key to a receiving terminal apparatus with which the encryption key is to be shared, the transmitting terminal apparatus comprising a processor and a memory, wherein the processor executes instructions stored in a memory and is configured to: generate a random block by randomly selecting and concatenating mask value blocks, each of the mask value blocks being consisted of only bits having 0 values or only bits having 1 values; generate a random bit sequence as the encryption key: encrypt communication data having an error detection code using the encryption key to generate encrypted data: generate an inquiry ID using a first bit sequence and the encryption key, the first bit sequence being obtained by XORing a group ID of the receiving terminal apparatus's affiliated group and the random block, the group ID of the receiving terminal apparatus XORing of which with a terminal ID of the receiving terminal apparatus consists of only a bit sequence concatenating the mask value blocks; generate a downlink message containing the inquiry ID and the encrypted data: and transmit the downlink message containing the inquiry ID and the encrypted data to multiple apparatuses in the receiving terminal apparatus's affiliated group, including the receiving terminal apparatus, wherein a number of bits of the encryption key equals a number of blocks into which the first bit sequence is divided; each of the bits of the encryption key corresponds to one of the blocks on a one-to-one basis; each bit value of the encryption key indicates a bit position in one of the corresponding blocks; and the inquiry ID is generated by inverting, in each of the blocks corresponding to the respective bits of the encryption key, a bit value at the bit position indicated by the bit value of the encryption key.