Securing digital identities in the cloud by selecting an apposite Federated Identity Management from SAML, OAuth and OpenID Connect

Access to computer systems and the information held on them, be it commercially or personally sensitive, is naturally, strictly controlled by both legal and technical security measures. One such method is digital identity, which is used to authenticate and authorize users to provide access to IT infrastructure to perform official, financial or sensitive operations within organisations. However, transmitting and sharing this sensitive information with other organisations over insecure channels always poses a significant security and privacy risk. An example of an effective solution to this problem is the Federated Identity Management (FIdM) standard adopted in the cloud environment. The FIdM standard is used to authenticate and authorize users across multiple organisations to obtain access to their networks and resources without transmitting sensitive information to other organisations. Using the same authentication and authorization details among multiple organisations in one federated group, it protects the identities and credentials of users in the group. This protection is a balance, mitigating security risk whilst maintaining a positive experience for users. Three of the most popular FIdM standards are Security Assertion Markup Language (SAML), Open Authentication (OAuth), and OpenID Connect (OIDC). This paper presents an assessment of these standards considering their architectural design, working, security strength and security vulnerability, to cognise and ascertain effective usages to protect digital identities and credentials. Firstly, it explains the architectural design and working of these standards. Secondly, it proposes several assessment criteria and compares functionalities of these standards based on the proposed criteria. Finally, it presents a comprehensive analysis of their security vulnerabilities to aid in selecting an apposite FIdM. This analysis of security vulnerabilities is of great significance because their improper or erroneous deployment may be exploited for attacks.