Research On Key Technologies Of E-government Security Engineering

E-government is promoting our state to perform information-based integration of management and service via modern information technology, achieving optimized reengineering of network-based organization structures and workflows, breaking through time, space and department limitation, providing high-quality, effective, formal, and transparent management and service to society in every aspect. Information security, being a core for state security, has always been one of the crucial issues restraining e-government construction and development. Although a set of technological architectures for e-government security engineering have been developed, there are still some fundamental issues worth looking into, such as bottleneck analysis and reduction for traditional security infrastructure, the application and security evaluation of identity-based cryptography in security infrastructure, security integration for applications in complicated multi-domain environment, duty tracing in transactions, protocol-based key recovery mechanism, secure authentication in SSL/TLS-based system and etc.This thesis is in depth concerned with the research on several key technologies in e-government security engineering, including the optimization for revocation management in traditional public key infrastructure PKI and privilege management infrastructure PMI, security evaluation of identity-based public key infrastructure, complicated multi-domain federated identity management, fair non-repudiation for online transaction, protocol-based key recovery and its application in network-layer and transport layer virtual private networks, and SSL/TLS man-in-the-middle attack and protection.The thesis makes several contributions, including:1. We analyze the application bottlenecks of traditional public key infrastructure and privilege management infrastructure; Aiming at revocation problem, an D-OCSP service mode for distributed environment and an Chinese standard draft-Simple online certificate status protocol S-OCSP-are proposed; the former exploits the idea of offline cryptography, removes secret information from online RTC responder and places them in RTCA server which stays offline. RTCA generates OCSP response proof set according to the status set of all the certificates issued by CA and publishes the proof set to all the RTC responders which use them to process OCSP requests sent from relying parties. By this way, distributed OCSP solves the issues in scalability, availability and security brought by "Trusted OCSP" radically and OCSP service is optimized as a whole; the latter, as a supplement for standard OCSP, is used to provide high performance for revocation checking in application servers. Experiments manifest that S-OCSP owns better performance than standard OCSP and reduces the cost of certificate revocation in application servers.2. Compared with traditional PKI, identity-based PKI is introduced and a comprehensive security evaluation is done, including trusted delivery of system parameters, secure private key issuing, key escrow, multi-domain support, integration with traditional PKI and etc. A new secure group-oriented content distribution scheme is presented, exploiting identity-based PKI. The scheme meets many essential requirements which include receiver access control, source authentication and non-repudiation, policy-driven encryption, obtains an O(1) cost for sender-side computation and communication, and owns properties such as simple group key management, low computation and communication cost, ease for implementation. It can be used to deploy commercial multicast content distribution system.3. Aiming at security issues of service federation in SOA-Based virtual organization, this paper discusses service federation by cross-domain service orchestration and choreography, analyzes critical security requirements of service federation for virtual organization, surveys the dominant technologies on federated identity management, proposes a security framework suitable for cross-domain service federation, and clarifies several fundamental security functions, such as trust topology management, federated sign-on/sign-out, attributed-based access control and delegation authorization and privacy protection. Finally, the interoperation of different federated identity management technologies is introduced.4. Two fair non-repudiation protocols are proposed based on Online-TTP mode. The former is used in traditional web applications based B/S architecture, and can be embedded in one round exchange for HTTP request and response. The latter applies to web services transactions and can be embedded into single web service call. Both protocols adopt evidence chaining to decrease the overhead of evidence verification and management and alleviate the overhead of certificate revocation checking and time-stamp generation for signatures. The protocols own properties of strong fairness, timeliness, efficiency and practicability.5. The paper analyzes protocol-based key recovery, discusses the advantages and disadvantages of identity based encryption, designs and implements protocol-based key recovery mechanism for IPSec, including four authentication methods-preshared key, signature, public key encryption and revised public key encryption, and two working mode-main mode and aggressive mode. Analysis on perfect forward security and IKEv2 is given. Experiments prove that it is easy to embed key recovery in IPSec VPN with valuable properties such as unfilterability, inter-operability, hidden key recovery and real time key recovery.6. Based on a comprehensive security analysis on SSL/TLS protocol and Chinese SSL VPN standard, a protocol-based key recovery scheme for SSL/TLS is given and its practicability is discussed. We present a proxy-based MITM attack scheme, give a dedicated analysis of security threat, and propose mechanisms for security enhancement, with a main focus on the session-aware MITM protection scheme. From the positive point of view, application of this attack in content filtering security, key recovery prevention and protocol customization is illustrated. A conclusion is that proxy-based MITM for SSL/TLS can be adopted to implement valuable function for positive security protection while it indeed brings us the noticeable security threat. An integrated session-aware S-ZTIC solution is designed, which can defend against both the MITM attack and malicious software attack.