Biblio

Digital identity is the key element of digital transformation in representing any real-world entity in the digital form. To ensure a successful digital future the requirement for an effective digital identity is paramount, especially as demand increases for digital services. Several Identity Management (IDM) systems are developed to cope with identity effectively, nonetheless, existing IDM systems have some limitations corresponding to identity and its management such as sovereignty, storage and access control, security, privacy and safeguarding, all of which require further improvement. Self-Sovereign Identity (SSI) is an emerging IDM system which incorporates several required features to ensure that identity is sovereign, secure, reliable and generic. It is an evolving IDM system, thus it is essential to analyse its various features to determine its effectiveness in coping with the dynamic requirements of identity and its current challenges. This paper proposes numerous governing principles of SSI to analyse any SSI ecosystem and its effectiveness. Later, based on the proposed governing principles of SSI, it performs a comparative analysis of the two most popular SSI ecosystems uPort and Sovrin to present their effectiveness and limitations.

Identity management is an essential cornerstone of securing online services. Service provisioning relies on correct and valid attributes of a digital identity. Therefore, the identity provider is a trusted third party with a specific trust requirement towards a verified attribute supply. This trust demand implies a significant dependency on users and service providers. We propose a novel attribute aggregation method to reduce the reliance on one identity provider. Trust in an attribute is modelled as a combined assurance of several identity providers based on probability distributions. We formally describe the proposed aggregation model. The resulting trust model is implemented in a gateway that is used for authentication with self-sovereign identity solutions. Thereby, we devise a service provider specific web of trust that constitutes an intermediate approach bridging a global hierarchical model and a locally decentralized peer to peer scheme.

As the number of Internet users increases, their usage also diversifies, and it is important to prevent Identity on the Internet (Digital Identity) from being violated. Unauthorized authentication is one of the methods to infringe Digital Identity. Multi-factor authentication has been proposed as a method for preventing unauthorized authentication. However, the cryptographic authenticator required for multi-factor authentication is expensive both financially and UX-wise for the user. In this paper, we design, implement and evaluate multi-factor authentication using My Number Card provided by public personal identification service and WebUSB, which is being standardized.

The emergence of Blockchain technology as the biggest innovations of the 21stcentury, has given rise to new concepts of Identity Management to deal with the privacy and security challenges on the one hand, and to enhance the decentralization and user control in transactions on Blockchain infrastructures on the other hand. This paper investigates and gives analysis of the most popular Identity Management Systems using Blockchain: uPort, Sovrin, and ShoCard. It then evaluates them under a set of features of digital identity that characterizes the successful of an Identity Management solution. The result of the comparative analysis is presented in a concise way to allow readers to find out easily which systems satisfy what requirements in order to select the appropriate one to fit into a specific scenario.

The collection of students' sensible data raises adverse reactions against Learning Analytics that decreases the confidence in its adoption. The laws and policies that surround the use of educational data are not enough to ensure privacy, security, validity, integrity and reliability of students' data. This problem has been detected through literature review and can be solved if a technological layer of automated checking rules is added above these policies. The aim of this thesis is to research about an emerging technology such as blockchain to preserve the identity of students and secure their data. In a first stage a systematic literature review will be conducted in order to set the context of the research. Afterwards, and through the scientific method, we will develop a blockchain based solution to automate rules and constraints with the aim to let students the governance of their data and to ensure data privacy and security.

Establishing a digital identity plays a vital part in the digital era. It is crucial to authenticate and identify the users in order to perform online transactions securely. For example, internet banking applications normally require a user to present a digital identity, e.g., username and password, to allow users to perform online transactions. However, the username-password approach has several downsides, e.g., susceptible to the brute-force attack. Public key binding using Certificate Authority (CA) is another common alternative to provide digital identity. Yet, the public key approach has a serious drawback: all CAs in the browser/OS' CA list are treated equally, and consequently, all trusts on the certificates could be invalidated by compromising only a single root CA's private key. We propose a Real Digital Identity based approach, or RDI, on decentralized PKI scheme. The core idea relies on a combination of well-known parties (e.g., a bank, a government agency) to certify the identity, instead of relying on a single CA. These parties, collectively known as Trusted Source Certificate Authorities (TSCA), formed a network of CAs. The generated certificates are stored in the blockchain controlled by smart contract. RDI creates a digital identity that can be trusted based on the TSCAs' challenge/response and it is also robust against a single point of trust attack on traditional CAs.

Including electronic identities (eIDs), such as passports or driving licenses in smartphones transforms them into a single point of failure: loss, theft, or malfunction would prevent their users even from identifying themselves e.g. during travel. Therefore, a secure backup of such identity data is paramount, and an obvious solution is to store encrypted backups on cloud servers. However, the critical challenge is how a user decrypts the encrypted data backup if the user's device gets lost or stolen and there is no longer a secure storage (e.g. smartphone) to keep the secret key. To address this issue, Password-Protected Secret Sharing (PPSS) schemes have been proposed which allow a user to store a secret key among n servers such that the user can later reconstruct the secret key. Unfortunately, PPSS schemes are not appropriate for some applications. For example, users will be highly unlikely to remember a cryptographically strong password when the smartphone is lost. Also, they still suffer from inefficiency. In this paper, we propose a new secret key reconstruction protocol based recently popular PPSS schemes with a Fuzzy Extractor which allows a client to recover secret keys from an only partially trusted server and an auxiliary device using multiple key shares and a biometric identifier. We prove the security of our proposed protocol in the random oracle model where the parties can be corrupted separately at any time. An initial performance analysis shows that it is efficient for this use case.