web3-encrypt v1.0.1
web3-encrypt
Provides methods for symmetric encryption/decryption using Ethereum addresses.
Usually when we use a web3 provider on a browser, such as MetaMask, Fortmatic, Bitski, etc., we do not have access to the private keys of accounts. Since we may want some secure mechanism for a user to store data on a server and retrieve it later, we need a workaround.
The method employed in this library is to take some arbitrary salt which the client can be assumed to always have access to, create a signature of that salt using the web3 provider, then use that signature as a symmetric key to encrypt some data. So long as the signature is never revealed, this should be a secure encryption method when we do not have access to private keys.
Installation
Node
npm install web3-encrypt
Usage
const {
Web3Encryption, web3Encrypt, web3Decrypt, constructWeb3
} = require('web3-encrypt')
/*
constructWeb3 takes an http provider url and returns a web3 instance
but you can provide your own Web3 object to Web3Encryption
*/
const web3 = constructWeb3('https://mainnet.infura.io/v3');
const account = web3.eth.accounts.create();
const message = 'hello crypto boys'
const salt = 'special-salt'
async function testCryptoFunctions() {
const cipher = await web3Encrypt(web3, account, message, salt)
console.log(`cipher from encrypt function: ${cipher}`)
const decipher = await web3Decrypt(web3, account, cipher, salt)
console.log(`deciphered message: ${decipher}`)
console.log(`deciphered message ${decipher == message ? 'matches' : 'does not match'} original`)
}
testCryptoFunctions()
`
> cipher from encrypt function: f7b5efbe6d7ac17d89032ba428acfc89f10cf5fc10305732ee1b741f1f73b4a2
> deciphered message: hello crypto boys
> deciphered message matches original
`
async function testCryptoObject() {
const w3crypto = new Web3Encryption(web3, account, salt)
const cipher = await w3crypto.encrypt(message)
console.log(`cipher from encrypt function: ${cipher}`)
const decipher = await w3crypto.decrypt(cipher)
console.log(`deciphered message: ${decipher}`)
console.log(`deciphered message ${decipher == message ? 'matches' : 'does not match'} original`)
}
testCryptoObject()
`
> cipher from encrypt function: f7b5efbe6d7ac17d89032ba428acfc89f10cf5fc10305732ee1b741f1f73b4a2
> deciphered message: hello crypto boys
> deciphered message matches original
`
web3Encrypt(web3, account, message, salt)
Params
- web3
object
- Instance of a Web3 object - account
object
- Instance of an Ethereum account, such as from web3.eth.accounts - message
string
- The message to encrypt - salt
string
- The salt input which is signed by the web3 account
Returns: Promise<string>
Cipher text after encryption
web3Decrypt(web3, account, cipher, salt)
Params
- web3
object
- Instance of a Web3 object - account
object
- Instance of an Ethereum account, such as from web3.eth.accounts - cipher
string
- The ciphertext to decrypt - salt
string
- The salt input which is signed by the web3 account
Returns: Promise<string>
Decrypted message
Web3Encryption.encrypt(message, options)
Calls web3Decrypt() using the Web3Encryption instance properties or the overridden options Params
- message
string
- The message to encrypt - options
object
- Optional properties- salt
string
- The salt input which is signed by the web3 account - web3
object
- Instance of a Web3 object - account
object
- Instance of an Ethereum account, such as from web3.eth.accounts
- salt
Returns: Promise<string>
Cipher text after encryption
Web3Encryption.decrypt(cipher, options)
Calls web3Decrypt() using the Web3Encryption instance properties or the overridden options Params
- cipher
string
- The ciphertext to decrypt - options
object
- Optional properties- salt
string
- The salt input which is signed by the web3 account - web3
object
- Instance of a Web3 object - account
object
- Instance of an Ethereum account, such as from web3.eth.accounts
- salt
Returns: Promise<string>
Cipher text after encryption