Research On Security Of Typical Routing Protocols In Communication Subnetworks Of The Internet

With the advances in Internet Technologies, network applications have stepped deeply into the human society, spanning from economics, industries, politics, cultures, and military affairs. For the very reason, the ghost of network insecurity has been threatening the human society hence drawing tremendous research efforts worldwide. Apart from the efforts aiming for an NGI with a "clean slate network architecture" intending to solve all the problems facing with the Internet (including the security issues), the majority of the security research activities have been given to the improvement of the security in the existing Internet. As a part of NGI research at the Sichuan Network Communication Key Lab, the research work presented in this PhD thesis has, by and large, focused on improving the security in the existing Internet.The analysis of the existing research work on network security has shown that most activities tend to be problem-solving oriented. Instead, this thesis starts to analyze network security issues from the perspectives of Internet architecture and treats system interconnection. The analysis of the architecture of communication subnetworks shows that OSI/RM and analogical OSI/RM follow the view of In-band signaling implicitly. That is, communication subnetworks are described as a three-layer structure, which ignores the differences in functions and structures between user data transmission& exchange platform and data transmission management platform as well as in security issues. With the out-of-band signaling concept, this thesis pinpoints that the communication subnetworks can be boil down to a three-layer "user-data transmission& exchange" platform (U-P) and a seven-layer (at most five-layer) signaling management platform (S&M-P) related to the upper signaling control management protocols. The responsibilities and the security are quite different in different platforms, and thus the concept of platform security is introduced. Taking the Internet as a complex system formed of interconnected Autonomous Systems (AS), the security problems of studying object can be fell into two groups, internal and boundary ones, and the concept of boundary security is highlighted. With these viewpoints, through analyzing two types of typical instances of resource subnetworks and communication subnetworks, this thesis focuses on two important protocols in S&M-P for communication subnetworks. That is, the Border Gateway Protocol (BGP) runs in gateways among interconnected ASs, and the most popular routing protocol within an AS-Open Shortest Path First protocol (OSPF). Detailed discussion is presented in Chapter 2 of this thesis.Chapters 3 to 6 are devoted to the research on security issues pertinent to BGP and OSPF and represent author’s main research results of the thesis. Chapter 3 intends to improve efficiency and to reduce the cost in the attestation mechanism of the classic BGP security solution S-BGP, while at the same time ensuring the security qualities-including unforgeable for participants, authenticity for IP address prefix, untampered for ASPATH, and mutual trustworthiness among Key Nodes (KN). As a result, a novel light-weighted routing attestation algorithm called SR-KN is introduced. The simulation results with a network of 110 ASs have shown that the network convergence time is about halved compared with S-BGP. When the number of ASs reaches 11038, the size of certificates is reduced to about seven thousandth.Traditional BGP security solutions adopt the centralized authentication model, hence they are difficult to be deployed and expanded. These problems are somehow addressed by the solution SE-BGP based on the Trust Translator Model (TTM); nevertheless, they are difficult in validating the identity of Cross-alliance ASs (CAA) and the authorization for their behaviors as well as in preventing their own-launched active attack. Chapter 4 introduces a novel scheme called Secured Cross-Alliance BGP (SCA-BGP) together with an authentication algorithm for crossing alliance and an anti-active-attack algorithm to cope with these problems. The required security quality of SCA-BGP has been theoretically proved and its superiority over S-BGP and SE-BGP, both in the scalability and network performance, has also been shown in simulation results.In chapter 5, further improvement has been made to SCA-BGP with regard to the robustness of the scheme and to the resource assignment issue, in view that cross-alliance trust translation depends on non-coordinated nodes. A Distributed Translator Trust Model DTTM is first established by the selected multiple KNs to apportion the trust translation tasks; then a restoration and reputation mechanism is built based on the neighbor-ring structure to enable Coordinated Secured BGP (CS-BGP). The theory proves that, the issue of resource assignment has been solved and the robustness has been improved. The experiment results have shown that as same as SCA-BGP, CS-BGP also has good scalability and network performance.Chapter 6 turns to the internal security issue of an AS and focuses on the research of OSPF security. Through expanding the existed two-layer structure in OSPF to a three-layer one, using the existed communication method among multiple members from different security groups, an efficient secured OSPF solution for the "area" structure-Hierarchical Secure OSPF (HS-OSPF) is proposed. The security features of HS-OSPF, such as confidentiality, authenticity, and completeness of information in flooding, undeniable and unforgeability of the identity for participants, and the controllable of threat are theoretically proved. The simulation results further show that the total time for obtaining the keys and the verification of HS-OSPF is far less than traditional methods and the numbers of keys to be stored will be reduced to one twentieth of traditional one with 1000 nodes divided into 10 areas.In summing up, starting from two different perceptions, i.e. platform and system interconnection, the thesis investigated the security issues of two routing protocols (BGP and OSPF) in details and made various improvements after pinpointing them through analysis of two typical systems:communication subnetworks and resource networks. The experiment results have shown that author’s schemes and algorithms not only provide better security for that platform, but also increase processing efficiency with better expandability. It should be noted that this thesis is restricted to the security issues of two routing protocols on the S&M-P restricted by timescale even though there are more protocols left behind. Nevertheless, the author believes that research on security issues of other protocols on the platform, such as SNMP and DNS, can also be carried out from the two perceptions mentioned above.