Developer Docs

Overview

Decentralized ID (DID) tokens are used as cryptographically-generated proofs that are used to manage user access to your application’s resource server. By adapting W3C’s Decentralized Identifiers (DID) protocol, the DID token created by the Magic client-side SDK (see getIdToken) leverages the Ethereum blockchain and elliptic curve cryptography to generate verifiable proofs of identity and authorization. These proofs are encoded in a lightweight, digital signature that can be shared between client and server to manage permissions, protect routes and resources, or authenticate users. The DID token is encoded as a Base64 JSON string tuple representing **[proof, claim]**:

proof: A digital signature that proves the validity of the given claim.
claim: Unsigned data the user asserts. This should equal the proof after Elliptic Curve recovery.

JavaScript

const claim = javascript.stringify({ ... }); // Data representing the user's access
const proof = sign(claim); // Sign data with Ethereum's `personal_sign` method
const DIDToken = btoa(JSON.stringify([proof, claim]));

Use Cases

Users have control over their own identity without relying on a central authority
DIDs can be used for secure authentication and authorization processes

Usage

Generating a DID Token (Pseudo-code)

JavaScript

// Construct the user's claim
const claim = JSON.stringify({
    iat: Math.floor(Date.now() / 1000),
    ext: Math.floor(Date.now() / 1000) + lifespan,
    iss: `did:ethr:${user_public_address}`,
    sub: subject,
    aud: audience,
    nbf: Math.floor(Date.now() / 1000),
    tid: uuid(),
});

// Sign the claim with the user's private key
// (this way the claim is verifiable and impossible to forge).
const proof = sign(claim);

// Encode the DIDToken so it can be transported over HTTP.
const DIDToken = btoa(JSON.stringify([proof, claim]));

Token Specification


Key	Description
`iat`	Issued at timestamp (UTC in seconds).
`ext`	Expiration timestamp (UTC in seconds).
`nbf`	Not valid before timestamp (UTC in seconds).
`iss`	Issuer (the signer, the “user”). This field is represented as a Decentralized Identifier populated with the user’s Ethereum public key.
`sub`	The “subject” of the request. This field is populated with the user’s Magic entity ID. Note: this is separate from the user’s Ethereum public key.
`aud`	Identifies the project space. This field is populated with the application’s Magic entity ID.
`add`	An encrypted signature of arbitrary, serialized data. The usage of this field is up to the developer and use-case dependent. It’s handy for validating information passed between client and server. The raw data must already be known to the developer in order to recover the token!
`tid`	Unique token identifier.

Resources

Decentralized ID - (W3C)

Embedded Wallets

Authentication

Wallets

SDKs

Blockchains

Decentralized ID (DID) Tokens

Overview

Use Cases

Usage

Generating a DID Token (Pseudo-code)

Token Specification

Resources

​Overview

​Use Cases

​Usage

​Generating a DID Token (Pseudo-code)

​Token Specification

​Resources

Overview

Use Cases

Usage

Generating a DID Token (Pseudo-code)

Token Specification

Resources