Abstract: A joining structure includes a first member having a cylindrical hollow portion, and a second member that is cylindrical in shape, has an outer circumferential diameter equal to or larger than a diameter of the hollow portion, and is to be pressed into the hollow portion. A concave portion, which is cut out inward from an outer circumference of the first member, is formed on part of a portion of the first member into which the second member is pressed.

Abstract: A secure, inexpensive, convenient payment system which allows an existing communication to be used to make an expensive payment terminal unnecessary, makes local communication unnecessary to make it possible to use the system by a seller and a buyer, uses closed-loop type electronic money to make it possible to make payment on delivery is obtained. An account database 6 which is arranged as equipment of a communication carrier and manages accounts of sellers and buyers (users), and a payment server 5 which is arranged as equipment of the communication carrier and performs an electronic payment process between the seller and the buyer are arranged. In the payment server 5, a primary payment server 3 and a secondary payment server 4 are arranged. When a payment request from a user is received through a communication network 10, the primary payment server 3 refers to the account database 6 to perform a real-time payment process by electronic money as primary payment between accounts of the seller and the buyer.

Abstract: A joining structure includes a first member having a cylindrical hollow portion, and a second member that is cylindrical in shape, has an outer circumferential diameter equal to or larger than a diameter of the hollow portion, and is to be pressed into the hollow portion. A concave portion, which is cut out inward from an outer circumference of the first member, is formed on part of a portion of the first member into which the second member is pressed.

Abstract: To provide a mobile communication system that can prevent unauthorized use of an encryption key otherwise caused by loss thereof and that can securely perform a direct communication between terminals using the encryption key. A portable terminal apparatus 1-1 transmits a P2P communication trigger to a portable terminal apparatus 1-n through a key managing/distributing server 3. In response to the transmission/reception of the trigger, the portable terminal apparatuses 1-1 and 1-n establish IPsec data sessions with the key managing/distributing server 3 through a SIP server 2 and a secret key is distributed per communication to the portable terminal apparatuses 1-1 and 1-n from the key managing/distributing server 3. The portable terminal apparatuses 1-1 and 1-n establish an IPsec data session therebetween using the secret key, thereby performing a P2P communication.

Abstract: A secure, inexpensive, convenient payment system which allows an existing communication to be used to make an expensive payment terminal unnecessary, makes local communication unnecessary to make it possible to use the system by a seller and a buyer, uses closed-loop type electronic money to make it possible to make payment on delivery is obtained. An account database 6 which is arranged as equipment of a communication carrier and manages accounts of sellers and buyers (users), and a payment server 5 which is arranged as equipment of the communication carrier and performs an electronic payment process between the seller and the buyer are arranged. In the payment server 5, a primary payment server 3 and a secondary payment server 4 are arranged. When a payment request from a user is received through a communication network 10, the primary payment server 3 refers to the account database 6 to perform a real-time payment process by electronic money as primary payment between accounts of the seller and the buyer.