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Guides (EVM)Sign Messages and Data

Sign Messages and Data

WaaP makes it easy to sign messages and data across all supported EVM-compatible blockchains. The SDK abstracts away cryptographic complexity and gas management, while remaining fully compatible with standard Ethereum interfaces.

Overview

  • Signing: Sign arbitrary messages and data for authentication, off-chain actions, or user intent verification.
  • Multi-Chain Support: Works seamlessly across all supported EVM chains, with automatic chain switching and gas management via the Gas Tank.

Usage

All signing methods are available via the WaapProvider object returned by initWaaP() from the @human.tech/waap-sdk package.

import { initWaaP } from "@human.tech/waap-sdk";
 
initWaaP();

Message Signing

personal_sign

Sign an arbitrary message with the user’s WaaP wallet. This is useful for authentication, off-chain actions, or verifying user intent.

// message example
const message = 'Hello World!';
 
const signature = await window.waap.request({
  method: "personal_sign",
  params: [message, address],
});
  • message: The string message to sign.
  • address: The user’s EVM address.

Note: The signature is EIP-191 compliant and can be verified using standard Ethereum libraries.

Demo

Advanced: Typed Data Signing

eth_signTypedData_v4

Sign EIP-712 typed data (structured data) for advanced use cases like DeFi, DAOs, and more.

 
// typedData example
const typedData = {
  types: {
    EIP712Domain: [
      { name: 'name', type: 'string' },
      { name: 'version', type: 'string' },
      { name: 'chainId', type: 'uint256' },
      { name: 'verifyingContract', type: 'address' }
    ],
    Message: [
      { name: 'content', type: 'string' },
      { name: 'timestamp', type: 'uint256' }
    ]
  },
  primaryType: 'Message',
  domain: {
    name: 'WaaP Demo',
    version: '1',
    chainId: 1,
    verifyingContract: '0x0000000000000000000000000000000000000000'
  },
  message: {
    content: 'Hello World!',
    timestamp: Math.floor(Date.now() / 1000)
  }
};
 
const signature = await window.waap.request({
  method: "eth_signTypedData_v4",
  params: [address, JSON.stringify(typedData)],
});
  • address: The user’s address.
  • typedData: The EIP-712 typed data object.

Demo

Security and User Experience

  • User Consent: All signing and transaction actions require explicit user approval via the WaaP modal.
  • No Private Key Exposure: Uses Two-Party Computation (2PC) where the private key is split into shares between the user’s device and the authentication server, ensuring the full private key is never reconstructed or exposed.
  • Multi-Chain: The SDK handles chain switching and ensures transactions are sent to the correct network.
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