makahiki.js

The smart account SDK for Stackup's onchain financial platform.

Getting started

This library enables interactions with a smart account composed of the following components:

• Kernel for the core ERC-7579 account.
• Smart Sessions for granular permissions.
• Account Modules for miscellaneous authentication and authorization modules.

The package itself builds on top of viem's account abstraction interface.

Installation

Note: this SDK uses a [email protected] and [email protected]. It is recommended to pin these versions to avoid typing issues.

pnpm install makahiki

Initialize smart account

import { http, pad } from "viem";
import { sepolia } from "viem/chains";
import { toSmartAccount } from "makahiki";

const account = await toSmartAccount({
  rootPublicKey,
  signerPublicKey,
  webAuthnAccount,
  publicClientConfig: {
    chain: sepolia,
    transport: http("Your node rpc here..."),
  },

  // Optional fields
  salt: pad("0x00", { size: 32 }),
  nonceKey: 0n,
});

Initialization options

| Option | Description | | ------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | | rootPublicKey | A hex public key of the root admin that deployed the smart account. Equivalent to viem's webAuthnAccount.publicKey. This determines the counterfactual address. | | signerPublicKey | A hex public key of the current signer for outgoing transactions. Equivalent to viem's webAuthnAccount.publicKey. | | webAuthnAccount | The webAuthn interface for the current user. See here. | | publicClientConfig | The same config object to initialize a viem Public Client. Note that chain is required. See here. | | salt | A 32 byte hex string that is used to derive the smart account address. Defaults to the zero hash. (Optional) | | nonceKey | A bigint value to set the key for the 2D nonce. Defaults to 0. (Optional) |

Return type

Returns an instance of a viem SmartAccount.

Encoding sessions

Access controls are built on top of the Smart Sessions module. We also export a collection of helper functions to work with sessions built for the Stackup use case.

WebAuthnSession

These are sessions tied to a WebAuthn passkey. Below are code examples for adding and removing pre defined sessions.

import { encodeFunctionData } from "viem";
import {
  SmartSession,
  WebAuthnSession,
  IntervalSpendingLimitPolicy,
} from "makahiki";

// Encode a function call to enable a sudo session.
const sudoCallData = encodeFunctionData({
  abi: SmartSession.abi,
  functionName: "enableSessions",
  args: [[WebAuthnSession.initSudoSession(p256Credentials.publicKey)]],
});

// Encode a function call to enable a limited spender session.
const spenderCallData = encodeFunctionData({
  abi: SmartSession.abi,
  functionName: "enableSessions",
  args: [
    [
      WebAuthnSession.initLimitedSpenderSession(p256Credentials.publicKey, {
        token, // Address, for ETH use IntervalSpendingLimitPolicy.NATIVE_TOKEN_FLAG
        value, // bigint
        interval, // "Daily" | "Weekly" | "Monthly"
      }),
    ],
  ],
});

// Encode a function call to remove a signer's session.
const removeCallData = encodeFunctionData({
  abi: SmartSession.abi,
  functionName: "removeSession",
  args: [WebAuthnSession.getPermissionId(p256Credentials.publicKey)],
});

There are also several additional utility functions for encoding ids and signatures.

// Get a permissionId for a given passkey.
const pid = WebAuthnSession.getPermissionId(p256Credentials.publicKey);

// Encode a session signature for a UserOperation.
const sig = WebAuthnSession.encodeSignature(p256Credentials.publicKey, {
  authenticatorData,
  clientDataJSONPre,
  clientDataJSONPost,
  challengeIndex: BigInt(challengeIndex),
  typeIndex: BigInt(typeIndex),
  r,
  s,
});

SessionUtils

Generic utility functions for working with Stackup + Smart Sessions is also available under the SessionUtils namespace.

import { SessionUtils } from "makahiki";

For a full list of available function see session/utils.ts.

Contributing

Steps for setting up a local dev environment for contributing to makahiki.js.

Prerequisites

• Node >=18.0.0

Setup

Install dependencies:

pnpm install

Run tests:

pnpm test

License

Distributed under the MIT License. See LICENSE for more information.