Solidity and MetaMask Cryptography – How to Encrypt a Message Without Direct Private Key Usage

thx @Edmunx Edgar, i tried to use ECIES, but it failed to install because of a subdepencency. I now used the bitcore-lib together with bitcore-ecies. This works like expected.

EDIT: I created a npm-module which does exactly theses things and also has some performance optimisations and tutorials: github:eth-crypto.

Here is my code for anyone with the same question:

// run 'npm install eth-crypto --save'

const EthCrypto = require('eth-crypto');

// create identitiy with key-pairs and address
const alice = EthCrypto.createIdentity();

const secretMessage = 'My name is Satoshi Buterin';
const encrypted = await EthCrypto.encryptWithPublicKey(
    alice.publicKey, // encrypt with alice's publicKey
    secretMessage
);

const decrypted = await EthCrypto.decryptWithPrivateKey(
    alice.privateKey,
    encrypted
);

if(decrypted === secretMessage) console.log('success');

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Currently, Metamask doesn't provide any such functionality. A discussion is going on to make some relative update. You can stay tuned: https://github.com/MetaMask/metamask-extension/issues/1190