Decentralized Digital Identity: DIDs, Credentials and the Projects Building Them
Decentralised identity lets people prove who they are – or just one fact about themselves – without handing their data to a platform. We explain the standards and review the projects.
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What is decentralized digital identity?
In today’s web, identity is issued and stored by platforms and governments. Every service keeps its own copy of your data, and a breach at one company can expose millions of records. Decentralised identity, also called self-sovereign identity, flips this model: identifiers and credentials sit in a wallet the user controls, and anyone can verify them cryptographically without contacting the issuer each time.
The building blocks
| Component | What it does | Example |
|---|---|---|
| Decentralized Identifier (DID) | A W3C-standardised identifier controlled by its subject through keys | did:key, did:web, did:ethr |
| Verifiable credential | A signed claim issued to a holder and checked by a verifier | “Over 18”, “KYC completed”, a diploma |
| Zero-knowledge proof | Proves a statement about a credential without revealing the data | Proving age without showing a birth date |
| Naming system | Maps a readable name to addresses and profile records | ENS names such as name.eth |
How a credential flow works
- An issuer – for example a bank or university – signs a credential about you.
- You store it as the holder in an identity wallet.
- A verifier asks for proof, and you share only what is needed.
- The verifier checks the issuer’s signature, often against a public registry, without calling the issuer.
Where decentralized identity is used
Typical use cases include reusable KYC, Sybil resistance for airdrops and governance, access control in DAOs, proof of personhood and portable reputation. Outside crypto, governments are moving in a similar direction: the EU’s eIDAS 2.0 framework introduces European digital identity wallets based on comparable ideas of user-held credentials.
The hard problems
The technology works; adoption is harder. Credentials are only useful if trusted issuers sign them and verifiers accept them. Users also need a way to recover lost keys without handing control back to a central party. Our reviews look at who issues credentials on each platform, how recovery works and what personal data, if any, ends up on-chain.
How we review identity projects
We look at which standards a project supports, whether credentials are portable to other wallets, how privacy is protected, how keys can be recovered and whether real issuers – banks, universities, governments or employers – actually use it.
Risks to keep in mind
- Personal data written to a public blockchain cannot be deleted – good designs keep it off-chain.
- Linking one identity across many apps can increase tracking rather than reduce it.
- Proof-of-personhood systems that collect biometrics raise additional privacy and regulatory questions.
Frequently asked questions
What is a DID?
A Decentralized Identifier (DID) is a globally unique identifier defined by a W3C standard. It is controlled by its subject through cryptographic keys rather than by a central registry.
Is ENS a decentralized identity?
ENS (Ethereum Name Service) is a naming system that maps readable names to addresses and records. It is often used as a building block of Web3 identity, but on its own it does not verify who a person is.
How do zero-knowledge proofs help identity?
They let a user prove a fact – for example that they are over 18 or not on a sanctions list – without revealing the full credential or personal data.
This page is for educational purposes only and is not financial, investment or tax advice. Crypto assets are volatile and you can lose all of the money you invest.
