@dfinity/identity

What is @dfinity/identity?

@dfinity/identity is an npm package that provides tools for managing identities and authentication in applications built on the Internet Computer. It allows developers to create and manage identities, sign messages, and interact with the Internet Computer's identity system.

What are @dfinity/identity's main functionalities?

Creating an Identity

This feature allows you to create a new identity using the Ed25519 key pair. The identity can be used for authentication and signing messages.

const { Ed25519KeyIdentity } = require('@dfinity/identity');
const identity = Ed25519KeyIdentity.generate();

Signing a Message

This feature demonstrates how to sign a message using an identity. The signed message can be used to verify the identity of the sender.

const { Ed25519KeyIdentity } = require('@dfinity/identity');
const identity = Ed25519KeyIdentity.generate();
const message = new TextEncoder().encode('Hello, Internet Computer!');
const signature = identity.sign(message);

Using an Identity with an Agent

This feature shows how to use an identity with an HttpAgent to interact with the Internet Computer. The agent uses the identity for authentication when making requests.

const { HttpAgent } = require('@dfinity/agent');
const { Ed25519KeyIdentity } = require('@dfinity/identity');
const identity = Ed25519KeyIdentity.generate();
const agent = new HttpAgent({ identity });

Other packages similar to @dfinity/identity

ethers

Ethers.js is a library for interacting with the Ethereum blockchain. It provides similar functionalities for managing identities and signing messages, but it is specific to Ethereum. Unlike @dfinity/identity, which is tailored for the Internet Computer, ethers.js is designed for Ethereum and its ecosystem.

web3

Web3.js is another library for interacting with the Ethereum blockchain. It offers features for managing accounts, signing transactions, and interacting with smart contracts. While it shares some functionalities with @dfinity/identity, it is focused on Ethereum rather than the Internet Computer.

did-jwt

did-jwt is a library for creating and verifying JSON Web Tokens (JWT) using Decentralized Identifiers (DIDs). It provides identity management and message signing capabilities similar to @dfinity/identity, but it is more general-purpose and not specific to the Internet Computer.

README

@dfinity/identity

JavaScript and TypeScript library to manage Identities and enable simple Web Authentication flows for applications on the Internet Computer

Do you want to know more about developing on the Internet Computer? Visit the Developer Docs.

Additional API Documentation can be found here.

Installation

Using authentication:

npm i --save @dfinity/identity

note: if you are using Secp256k1KeyIdentity, you will also need to install crypto-browserify as a PeerDependency. It is left out of project dependencies to keep @dfinity/identity smaller.

In the browser:

import * as identity from '@dfinity/identity';

or using individual exports:

import { ECDSAKeyIdentity, DelegationIdentity } from '@dfinity/identity';

ECDSAKeyIdentity

Using an ECDSAKeyIdentity, you can now use the native Web Crypto API to manage your keys in agent-js. ECDSAKeyIdentity uses the crypto.subtle interface under the hood, and wraps the conventions for managing identities in the same way as other identities in this package.

Importantly, there is no importing from a private key or from JSON for this library. This should be used only in secure contexts, and you should only in rare circumstances interact directly with the KeyPair or CryptoKeys involved. Importantly, your CryptoKeys can be used in IndexedDb and can be created as extractable or non-extractable for enhanced security properties.

Secp256k1KeyIdentity

This identity can be generated using the bip39 curve from a seed phrase, to produce a consistent identity across dfx and agent-js. In this package, import Secp256k1KeyIdentity and call fromSeed, passing in your seed. You can import the same seed in dfx by writing it to a file, and running dfx identity import --seed-file <filename>.

Depending on the security of what this identity controls, this should not be used carelessly. Even copy/pasting a phrase can be a risk, and you should make your best efforts to discourage your users from storing seed phrases digitally or using them in browser contexts that may be at risk of cross-site scripting.

In Node.js

Depending on your version, you may need to use a polyfill and set global.crypto in a setup file. If you prefer, you can also pass in a subtleCrypto implementation in methods that call for it, either as a direct argument, or in a cryptoOptions object.

Note: depends on @dfinity/agent

Changelog

[3.1.0] - 2025-07-24

• feat: export the getCrc32 function from @dfinity/principal