# Siberia: A Self-Sovereign Identity and Multi-Factor Authentication Framework for Industrial Access
## 1 Introduction
### Self-Sovereign Identities
#### 1.1.1 Related Work on SSI  
SSI represents a paradigm shift in digital identity management, granting individuals full control over their personal data while eliminating the need for centralized authorities. This subsection reviews the most relevant surveys and studies on SSI, focusing on the core elements of SSI frameworks and the underlying technologies commonly employed. The selected works highlight the most representative and influential contributions in the field, providing an overview of the current state of technological maturity. The IdM system for public transportation was introduced in [12] as an SSI-based identity manager leveraging blockchain technology for a European public transport system. This system allowed students to access transport discounts using VCs issued and signed by their respective universities, which certify their student status. The proposed solution ensured secure and decentralized verification of student identities, enhancing privacy and autonomy. However, the design remained theoretical, with no practical implementation. The authors of [13] explore the application of SSI in IoT networks, comparing its implementation with Pretty Good Privacy (PGP) and X.509 standards. Their analysis examined core components and functionalities across these technologies. The study concluded that SSI was particularly advantageous in IoT environments, as it granted users full control over their identities, eliminated dependence on third parties, and enhanced privacy. The SSIBAC system was presented in [14] as an access control system based on SSI. The tool combined conventional access control elements with blockchain technology (using Sovrin) to provide decentralized authentication and centralized authorization. The system was validated in an academic context, where VCs represent academic information such as degrees or qualifications. In this way, students are the holders, educational institutions are the issuers, and verifiers are the potential employers. Finally, the authors of [15] proposed a theoretical SSI-based identity model for healthcare, a sector characterized by highly sensitive data. The study highlighted the potential of SSI to enhance patient confidentiality and ensure compliance with existing regulations. Recognizing the potential of such identity models and anticipating emerging trends and regulations related to identity and rights protection, several commercial solutions and products have been developed in recent years. These tools have demonstrated, to varying degrees, successful use cases and real-world applications, and therefore, they warrant discussion and analysis. Table 1 provides a comparison of their general characteristics. The tools are outlined below:  
* SelfKey [16] is a blockchain-based SSI management system based on Ethereum blockchain technology to ensure secure, private, and efficient identity verification processes. The SelfKey Marketplace offers access to various financial, immigration, and cryptocurrency services. Users can find and apply for products like bank accounts, residency, and company incorporation services directly through the SelfKey platform. The SelfKey ecosystem is powered by the KEY token (an ERC-20 token on the Ethereum blockchain), which is used for transactions within the network. KEY tokens facilitate identity verification services and access to the marketplace, and they incentivize participation in the SelfKey ecosystem. * Sovrin [17] is a decentralized, global public utility designed specifically for managing digital identities. It operates as an open-source, blockchain-based platform that enables individuals and organizations to create, manage, and verify digital identities. At the heart of the Sovrin Network is distributed ledger technology, which provides a tamper-proof record of identity transactions. This ledger is maintained by a network of independent standards, which are organizations that operate the nodes and uphold the integrity of the system. These standards include reputable institutions from various sectors.