Research On Multi-Level Security Of OpenID

As a new generation of solution to Single Sign-On (SSO), OpenID can simplify the user's operation process and reduce resource provider's overhead. The integrity of OpenID as an important aspect of multi-level security has become a hot issue. There are several models that can be used to guard the integrity of systems. Biba model is the most popular integrity model since it is stated with formal mathematical terms. The Strict Integrity Policy (SIP) of Biba model can be used to protect the integrity of data in computer systems, but it might decrease the compatibility of systems.The basic OpenID infrastructure is introduced firstly, including its components, hierarchy and other key issues. A simple prototype is also demonstrated to indicate its deploying and analyses its security features.Secondly, a dynamic determination scheme of subject's integrity level which is based on the subject's history behavior has been presented. The integrity level of the subjects is extended into separated reading and writing integrity level ranges, while the minimal integrity level of the data which the subject has read as well as the maximal integrity level of the receiver which the subject has written to is also tracked. The subject's access request is arbitrated according to its history behavior, together with its reading and writing integrity level ranges. The proof of it is also given, which shows that the scheme is secure. The security risk of the existing improved SIP is indicated by an example, and the main reason which leads to this phenomenon is also given. In addition, we point out that the scheme has the same time and space complexity as the common SIP after the comparisons and analysis. The scheme can improve the compatibility of the system while keeping the integrity as strict as SIP can, and it can be applied for several types of systems.Finally, interpretation on how to adapt the dynamic determination scheme to OpenID is given. The user's attribute information is stored in OpenID server. The user's access history list is established to track the read, write, read-write and invoke history behavior and it can decrease the redundant authentications between OpenID server and the Web source site. And the dynamic determination scheme for subject's integrity level of OpenID is constructed, which can be used to improve the compatibility and flexibility of OpenID while keeping the integrity.