I recently encountered a requirement to encrypt and decrypt messages in my project. After some research, I found a way to achieve this using @metamask/eth-sig-util. Below is the approach I used ( this is only available for Metamask as only Metamask is allowing encryption/decryption until now ).

Encryption
To encrypt the message, I used the encrypt function from @metamask/eth-sig-util:

import { encrypt } from "@metamask/eth-sig-util";

const encrypted = encrypt({
 publicKey: encryptionPublicKey,
 data: inputMessage, // The message to encrypt
 version: "x25519-xsalsa20-poly1305",
});

const encryptedString =
 "0x" + Buffer.from(JSON.stringify(encrypted)).toString("hex");

Decryption
To decrypt the encrypted message, I used eth_decrypt provided by MetaMask:

const decrypted = await window.ethereum.request({
method: "eth_decrypt",
params: [encryptedData, address],
});

• encryptedData is the encrypted message received.
• address is the Ethereum address that owns the decryption key.

This approach worked seamlessly in my project. Hope this helps someone facing a similar issue! 🚀

Let me know if you have any questions.