What is Digital Identity#
Identity is an essential characteristic for everyone. In traditional society, we use a series of physical materials to prove "I am who I am". These materials not only include proof of who I am, such as identification cards, but also include proof of a person's social relationships and behaviors, such as marriage certificates, driver's licenses, and diplomas, all of which are included in the concept of identity.
In the era of the Internet, physical materials have become electronic information, giving rise to digital identity. Digital identity is an identification in the network, and its core is to prove "I am who I am" by providing and verifying identity information.
Identity in Web2.0#
In Web2.0, in order to use the functions provided by the platform, users must authorize centralized third-party platforms to manage a large amount of data. Because of this, centralized companies have been given immense power and influence in terms of data and content permissions. They own user data and all user-generated content, which means that user identity and data are under control. Massive user data has become a tool for platforms to seek profits. Many individuals who should enjoy the convenience of the Internet are forced to become "data laborers" serving platform algorithms. Undoubtedly, this kind of violation of user data and identity is against the spirit of the Internet.
At the same time, the platform monopoly and territorialism in Web2.0 make social graphs and user relationships rigid. Users cannot migrate. If the original platform cannot be used for various reasons, it will be extremely cumbersome and complex to move your friends to a new platform.
The root cause of all this is the lack of corresponding identity mechanisms. The data of the original platform does not belong to the users themselves, and you still cannot prove the fact that "I am who I am".
Based on this situation, in the era of Web3.0, it has become a trend to attribute personal identity content to the users themselves and to give users ownership of their own identity data. Therefore, the solution of self-sovereign identity (SSI) has been proposed.
What is Self-Sovereign Identity#
Self-sovereign identity (SSI) is the concept that users have complete control over their own identity data. It is the center of identity management, with independent control, security, and full portability, not locked to a specific site or region.
Blockchain provides a distributed trust environment, which is a necessary technology for implementing self-sovereign identity. The core idea of blockchain-based self-sovereign identity is to create a globally unique identity identifier called DID, which has high availability, resolvability, and encryption verifiability.
What is DID#
Decentralized Identifier (DID) is a new type of identity identifier derived from traditional centralized identity. It refers to the decentralization of ownership, control, and management of one's own digital identity, fully belonging to individuals or organizations. The DID system mainly includes the basic layer of DID identifiers, DID documents, and the application layer of verifiable credentials (VC).
• DID Identifier: It is a globally unique identity identifier, similar to a person's ID card or account.
• DID Document: It describes how to use the DID in a simple document.
• Verifiable Credentials (VC): The DID document itself cannot be associated with the user's real identity information. VC is needed to achieve this. It is the value of the entire system. VC is similar to a digital certificate and is proof of a user's identity.
DID itself is just an identity identifier and does not need to be stored on the blockchain. However, by combining blockchain with DID, users can have full control over all identity information and achieve a single identity, truly realizing self-sovereign identity and data autonomy, and protecting the rights and data privacy of user applications. See the figure below:
"It can be said that self-sovereign identity (SSI) includes decentralized identity (DID)."
DID, as a fundamental infrastructure, derives more value not from itself, but from a series of data generated based on it.