# Self-Sovereign Identity-Based E-Portfolio Ecosystem
## 2 Background and Related Work
### Identity Management  
Text passwords are commonly used for authentication, but they rely on the trustworthiness of service providers. Users may reuse the same password for multiple services for convenience [24], but if a malicious provider gains access to the password, they can use the user's identity to log in to other services. Additionally, managing too many passwords can be difficult. To address these issues, some providers offer social login through tech giants like Google and Facebook. Social login allows users to use their digital identity to log in to multiple services without additional registration, but it still relies on centralized platforms, which raises concerns about the fraudulent use of user identities. Web-based digital identities (DIs) have gone through four stages of evolution [25]: centralized identity, federated identity [26], user-centric identity [27], and self-sovereign identity (SSI) [28; 29]. The traditional centralized approach to digital identity has been gradually losing its dominance as users demand greater control and autonomy over their identities. SSI [29] offers an innovative method for digital identity, enabling users to take full control of their identity management. SSI allows users to have distributed identities across multiple locations that are interoperable and portable, which means that they are not limited to specific websites or services. In [29], the Self-Sovereign Identity (SSI) framework is defined according to ten features: control, existence, transparency, access, persistence, consent, interoperability, portability, protection, and minimalization. The government utilizes a Decentralized Identifier (DID) chain to create user identities in the e-portfolio application chain, ensuring alignment with these SSI features. Notably, within the ten aspects, our identity in the e-portfolio application chain adheres to nine, excluding \"control\". The exclusion of the \"control\" attribute is justified as it is considered unnecessary for our system. It is noteworthy that a parallel research approach, as documented in [30], also omits this attribute. By adhering to these principles, agencies can help ensure that SSI is secure, transparent, and protects users' privacy. SSI has the capacity to revolutionize digital identity systems by giving users enhanced control and autonomy over their identities. Recently, blockchain technology has enabled the concept of SSI [28], according to which users have complete control of their own identities anchored in blockchain. Several studies have proposed self-sovereign identity-based digital identity platforms, such as \"Casper\" by [PERSON] et al. [31], which provides users with one identification stored in a mobile identity wallet to log in to different organizations. [PERSON] et al. [32] proposed the open-source \"uport\" identity management system to realize SSI and offer application developers a general authentication option. With blockchain technology, users' identities cannot be used fraudulently, providing users with more control and security. In [7], the authors propose a physiological data sharing platform via blockchain technology, incorporating both a decentralized identity chain (DID-chain) and a physiological data sharing chain. Their DID-chain meets nine out of the ten requirements of SSI [29], including existence, transparency, access, persistence, consent, interoperability, portability, protection, and minimalization. This consortium blockchain, developed in collaboration with government and regulatory authorities, aims to unify user identities across various ecosystems. Users and organizations must register using their real names through official government channels and undergo a verification process. Upon successful verification, they receive a personal identity contract (_Plcon_) that is exclusively controlled by the individual or organization. This contract is secured by a primary identity represented by a private key, which serves as a verification method for the authentic entity.