A Decentralized Group Key Management Scheme For The Decentralized P2P Environment

The peer-to-peer (P2P) networks have emerged as a solution for internet users to share the files efficiently and economically without the help of central servers. Since the Internet is an open distributed platform and it cannot guarantee the data security, information providers try to protect their information by cryptographic techniques. According to modern cryptology, the security of cryptographic system depends on secret keys. Therefore, efficiently managing keys for large, dynamically changing groups is one of the important problems in P2P networks.One-way function tree (OFT) can be regarded as a centralized key distribution scheme under the aspect that it relies on a single group key sever to generate and distribute the group keys to the group, and thus, lacks fault-tolerance. On the other hand, the tree-based group Diffie-Hellman (TGDH) scheme, a distributed key agreement scheme, is relatively inferior in terms of performance to OFT although it is fault-tolerant. To solve these problems, a decentralized group key management algorithm called DECOFT (Decentralized One-way Function Tree) which combines OFT and TGDH is proposed for the secure group communication in the decentralized P2P environment. DECOFT realizes group initialization, group key establishment, and member addition and eviction by decentralized group key management. In DECOFT, a group is divided into many subgroups that are independent of each other. In this scheme, OFT is employed for intra-subgroup key management and TGDH is employed for inter-subgroup key management.It is proved that DECOFT is a secure, simple and efficient scheme which is superior to TGDH in performance and solves the scalability and single point of failure problem of OFT. And the proposed algorithm, DECOFT, can make full use of P2P super nodes and is efficient for the decentralized P2P environment.