Provided is a transmitting terminal capable of sharing an encryption key among a number of specific apparatuses using fewer resources and securely. A transmitting terminal (400) has an inquiry ID generation unit (420) which embeds an encryption key in logical results of an XOR between an ID of a receiving terminal and random blocks according to predetermined key embedding rules in order to generate an inquiry ID. The key embedding rules are stipulations for inverting the values of bit positions corresponding to each bit value of the encryption key, in the block position correspondence relationships between the bit positions of the encryption key and the positions of the blocks into which the logical result of the XOR have been partitioned and the bit position correspondence relationships between the bit values of the encryption key and the bit positions within the blocks, which have been predefined.