Decentralized Identifiers (DID)
DIDs are unique identifiers that can be resolved to DID Documents containing public keys and URIs for identity verification and public information.
Adhering to the W3C's DID specifications, IOTA's implementation ensures interoperability and security within its ledger.
DIDs support self-sovereign identity, allowing identity owners to control their creation and destruction, while facilitating encrypted communication.
A DID is a unique identifier that can be resolved to a DID Document. This document contains data such as public keys, enabling the holder to prove ownership over their personal data, but also URIs that link to public information about the identity. DIDs are the fundamental building blocks of decentralized digital identity. This implementation complies with the DID specifications v1.0 from the World Wide Web Consortium (W3C).
In the IOTA Identity framework, we have implemented the DID standard according to the iota DID Method Specification. Other implementations of DID on IOTA must follow the iota DID Method Specification if they want to use the iota method name. Libraries implementing the iota DID Method Specification are provided for Rust.
Decentralized Identifiers
A Decentralized Identifier, or DID, is a unique identifier that is tied to a subject. This subject can be anything, like a person, an organization, an IoT device, or even an object. The identifier can be used by the subject to identify themselves through a digital format, providing a basis for online identification. The identifier looks like a set of random characters that includes some prefixes to determine which standard and implementation is used:
did:iota:0xe4edef97da1257e83cbeb49159cfdd2da6ac971ac447f233f8439cf29376ebfe
The World Wide Web Consortium (W3C) is a well-known standardization body that has standardized how DIDs should look and work. This provides a basis for different technologies that implement the DID standard to achieve interoperability. Keep in mind that, unfortunately, most of these methods are outdated and not maintained.
DID Documents
The purpose of a DID is to help navigate to a DID Document, which is a document containing more information regarding the identity subject. This document contains data such as public keys, enabling the subject to prove ownership over their personal data, but can contain additional information on how to interact with the subject.
The identifier contains all information to resolve a DID, providing the latest DID Document.
The first three characters did indicate that the DID standard from W3C must be used to resolve the identifier.
It is followed by a unique method name, in our case iota, to indicate that the IOTA method is used.
The IOTA method is a specific implementation following the IOTA DID Method Specification. This provides unique rules for the protocol to follow in order to manage a DID Document. In our case, it describes how DID Documents are uploaded and queried to and from the IOTA ledger.
Lastly, a DID also contains a set of random characters that are unique per identity and resolve to a single DID Document.
The following sections require some basic knowledge of Asymmetric Encryption. Please read or view some materials on the subject before continuing.
DID Document Anatomy
A DID Document mostly contains two important pieces of data: verification methods and services.
Verification Methods
Verification methods contain public key material that can be used to prove ownership over the identity, by cryptographically signing something with the associated private key. The public key can be used to verify that the identity subject signed the data and therefore controls the private key. Ownership over the private keys, therefore, proves ownership over the identity.
This also means that it is very important to keep the private keys safe and secure. In addition, the public keys allow users to send encrypted data to the identity that only the identity owner can decrypt.
Never share your private keys, seeds, passphrases with anyone. Not even IOTA Foundation members. This may lead to loss of funds or control over your own digital identity.
Services
Services are URIs that point to more information about the identity. This could be something as simple as a website for an organizational identity. These services are publicly available for all to read, and should not contain Personal Identifiable Information (PII) in the case of human identities.
Why Use DIDs?
DIDs allow any subject to have a unique identifier that they can prove ownership of, and at the same time provide a way to send them encrypted messages. The Identity is Self-Sovereign, meaning the subject is always in control; whether it is creating, updating, or destroying it.
Verifiable Credentials
DIDs become more interesting when you combine them with verifiable credentials (VC). In essence, verifiable credentials (VCs) are signed statements by trusted third parties about a certain identity. The signer, or Issuer, is referenced by the DID and so is the subject, often called the holder. The holder controls a copy of this statement and can share it with other parties, the Verifiers, who can verify the statement and check which party made the statement without asking the Issuer. Instead, they can verify the issuer's signature by checking the issuer's DID Document.
This puts Holders back in control over their own data, while making the data much more trustworthy as it has become verifiable.
Why Use Iota Identity Over Other Implementations?
IOTA Identity is a framework to implement Self-Sovereign Identities on IOTA. Inherently, IOTA provides some unique features that have a major impact on the usability of the framework.
Availability and Accessibility
DID Documents are stored in the ledger state and are covered storage deposit. This guarantees that all nodes will have an up-to-date copy of the latest DID Document. Resolving a DID into its document can usually be done by any IOTA node in the network. This solves many issues regarding availability, accessibility, and synchronization.
Layer1 Interactions
DID Documents are stored in Identity objects. This allows them to directly interact with other Layer 1 artifacts like NFTs and coins.
For instance, an Identity object representing a DID can hold coins or control NFTs. Transferring funds between DIDs is also possible on Layer 1.
Ease-of-use
IOTA Identity abstracts the details of the DID standard by providing easy-to-use APIs that allow standardized behavior. It also allows more flexible and complex management of DID Documents.