Modern financial institutions have cashed in on the electronic business opportunities of the Internet by developing numerous payment systems to meet various payment service requirements. Advanced computer systems and telecommunications technology are being used to offer fast, convenient, and secure ways to conduct financial transactions at service and security levels that are hardly or never achieved by traditional payment systems. In this paper, we examine the function and operation flow of the electronic funds transfer process as well as its security control mechanism. To evaluate telecommunication and data security techniques, a standard-leading inter-bank payment system called the Society for Worldwide Inter-bank Financial Telecommunications System is introduced. Some important security features are investigated in detail.