eth-ecies

ECIES encrypt/decrypt library for Ethereum

Usage

Encrypt

const ecies = require("eth-ecies");
let plaintext = new Buffer(`{foo:"bar",baz:42}`);
let encryptedMsg = ecies.encrypt(ethPubKey, plaintext);
// encrypted message is a 113+ byte buffer

Decrypt

const ecies = require("eth-ecies");
let plaintext = ecies.decrypt(ethPrivKey, encryptedMsg);

Notes

To derive the public key from a private key, you can use ethereumjs-util module

Security

The ECIES implementation uses fixed Diffie-Hellman (ephemeral-static) key exchange and provides no Perfect Forward Secrecy (PFS). A quick rundown of the implementation can be found here

Appropriate use cases of this library

• Encrypted file storage
• Encrypted emails (where forward secrecy is not desirable, e.g. being able to read past emails)

Inappropriate use cases

• Instant messaging for casual conversations