Security issues in peer-to-peer systems

Decentralization was an architectural principle of the Internet, but over a period of time, the Internet has changed significantly. Some even think the Internet is becoming increasingly centralized that it is fundamentally broken. The term "peer-to-peer" (P2P) is a collection of various systems and applications based on such decentralized architecture, which imply a variety of security means and tools on the client-server system cannot be applied. Such a high risks involved in P2P systems draw attentions on various security issues. The paper introduces various security issues, methods for protection, and suggestions for further enhancements on the security mechanism in P2P systems