There are a number of questions one might ask about security of money transactions on the Internet. A first question might be: "Why do we need to protect money transaction on the Internet?" The Internet is an insecure and unreliable communication medium - thus protection of sensitive data is needed. E-business systems inherently possess a higher degree of risk than mainstream applications, and thus require greater degree of security. Because of this risk, security should be considered a fundamental aspect of e-business system design. Especially big attention is dedicated to money transactions protection. There are dozens of electronic payment systems being developed to facilitate secure money transactions. The paper presents IPS (Internet payment system) software implementation. Distributed system architecture allowed us to watch system segments as independent systems connected by corresponding communication protocol. Segments are: Web shop, payment Web segment, merchant server, payment gateway server and bank server. They communicate through secure communication tunnel, which consists of SSL tunnel and nested crypto tunnel. IPS use different cryptographic algorithms and techniques to achieve: privacy, integrity, authentication and non-repudiation.