基于FMTseq方案的服务器辅助签名

对当前的公钥数字签名方案,如果签名方是一个计算机能力较弱的移动智能设备,则影响生成签名的速度和安全性。为此,我们通过引进第三方可证服务器与一次数字签名方案相结合,辅助签名方生成签名的方案,提出了一个基于一次数字签名的服务器辅助签名协议。

CIT/XML Security Platform Syntax and Processing

Today companies and organizations are using the Web as the main informationdissemination means both at internal and external level. Information dissemination often takes theform of XML documents that are made available at Web servers, or that are actively broadcasted byWeb servers to interested clients. These documents often contain information at different degrees ofsensitivity, therefore a strong XML security platform and mechanism is needed. In this paper wedeveloped CIT/XML security platform and take a close look to syntax and processing of CIT/digitalsignature model, CIT/encryption model, CIT/smart card crypto and SPKI interface security models.Security services such as authentication, integrity and confidentiality to XML documents and non-XMLdocuments, which exchanged among various servers, are provided.

Cryptanalysis of Two Dynamic Identity Based Authentication Schemes for Multi-Server Architecture

Since network services are provided cooperatively by multiple servers in the lnternet, the authentication protocols for multiserver architecture are required by Internetbased services, such as online game, online trade and so on. Recently, Li et al. analyzed Lee et al.＇s protocol and proposed an improved dynamic identity based authentication protocol for multi-server architecture. They claimed that their protocol provides user＇s anonymity, mutual authentication and the session key agreement against several kinds of attacks. In this paper, a cryptanalysis on Lee et al.＇s scheme shows that Lee et al＇s protocol is also vulnerable to malicious server attack, stolen smart card attack and leak-of-verifier attack. Moreover, Li e/ al.＇s improved protocol is also vulnerable to all these attacks. Further cryptanalysis reveals that Li et al.＇s improved protocol is susceptible to collusion attack.

RSA-based Proxy Signature for Media Independent Handover

This paper proposes an Authentication Interworking Protocol （AIP） based on IEEE 802.21 Medi Independent Handover （MIH） in the heterogeneous networks. The proposed AIP with the RSA-based proxy signature reduces handover delay time and communication message overhead when the mobile node moves between the heterogeneous networks. It defines new AlP Type Length Value （AlP TLV） in MIH frame format and uses the MIH Information Server （MIHIS） for issuing signature. The MIHIS can generate a signature on behalf of the AAA server and then the signature can he used by mobile node for a pre-authentication. For low handover delay, the proposed AIP performs pre-authentication processes with MIP protocol before layer 2 handover. Also, this paper analyses the performance of the handover and compares with the non-secure MIH.

DIV： Dynamic Integrity Validation Framework for Detecting Compromises on Virtual Machine Based Cloud Services in Real Time

with the increasing popularity of cloud services,attacks on the cloud infrastructure also increase dramatically.Especially,how to monitor the integrity of cloud execution environments is still a difficult task.In this paper,a real-time dynamic integrity validation(DIV) framework is proposed to monitor the integrity of virtual machine based execution environments in the cloud.DIV can detect the integrity of the whole architecture stack from the cloud servers up to the VM OS by extending the current trusted chain into virtual machine's architecture stack.DIV introduces a trusted third party(TTP) to collect the integrity information and detect remotely the integrity violations on VMs periodically to avoid the heavy involvement of cloud tenants and unnecessary information leakage of the cloud providers.To evaluate the effectiveness and efficiency of DIV framework,a prototype on KVM/QEMU is implemented,and extensive analysis and experimental evaluation are performed.Experimental results show that the DIV can efficiently validate the integrity of files and loaded programs in real-time,with minor performance overhead.

Entrenched Board in New Public Firms： An Empirical Study of Chinese IPOs

This study empirically investigates the impact of managerial entrenchment on firm financial performance of Chinese firms initial public offerings （IPOs）. Using 142 firms listed in the Shenzhen Stock Exchange （SZSE）, which was collected from the Guotaian Research Service Center （GTA-RSC） databases, this study uses two proxies to measure firm performance and three proxies to measure managerial entrenchment. The two proxies for firm performance are Tobins＇ Q and return on assets （ROA）, and the three proxies for managerial entrenchment are entrenchment 1, entrenchment 2, and entrenchment 3. These three entrenchment proxies are derived from the principal component analysis （PCA）. Though previous studies of managerial entrenchment and firm performance variables suffer from endogeneity, with respect to the corporate governance it is unclear as to which variables are endogenous and which are exogenous. This study confirms that the data are linear and no endogeneity issue should be address in this study, but only heteroskedasticity, non-normality for Tobins＇ Q are a problem, therefore, the regression method employed for Tobins＇ Q is the generalised least square （GLS） and the ordinary least square （OLS） between estimators for ROA. The regression result for Tobins＇ Q reveals that managerial entrenchment is negatively impact on firm performance. The results are in contradiction to the stewardship theory for new firms whereas the managerial entrenchment for new firms is positive. Furthermore, only one entrenchment proxy yields a significant coefficient. In conclusion, the negative results of entrenchment proxies were caused by the different institutional structures and legal systems which are the Chinese corporations that are still largely owned and controlled by a state and hence the centralised state controlled was responsible for all managerial actions.