encrypt and decrypt message with public key and private key

message_encrypt_decrypt_for_blockchain.js

/*

Requirement
--------------
node: v8.10.0
npm:  v5.6.0
--------------

npm installation
-----------------------
npm install eth-crypto
-----------------------

*/

const EthCrypto = require('eth-crypto')

const keyPrivate = '0x61ce8b95ca5fd6f55cd97ac60817777bdf64f1670e903758ce53efc32c3dffeb'
const keyPublic = 'fff49b58b83104ff16875452852466a46c7169ba4e368d11830c9170624e0a9509080a05a38c18841718ea4fc13483ac467d3e2d728d41ff16b73b9c943734f8'

const encryptStringWithPublicKey = async ({ message, publicKey }) => {
  const dataObject = await EthCrypto.encryptWithPublicKey(publicKey, message)
  const compressedString = await EthCrypto.cipher.stringify(dataObject)
  return compressedString
}

const decryptStringWithPrivateKey = async ({ encryptedString, privateKey }) => {
  const decompressedString = await EthCrypto.cipher.parse(encryptedString)
  const originalMessage = await EthCrypto.decryptWithPrivateKey(privateKey, decompressedString)
  return originalMessage
}


const startHacking = async () => {
  const msg = 'DEXON\'s latency is 1s'

  const encryptedString = await encryptStringWithPublicKey({
    publicKey: keyPublic,
    message: msg,
  })
  // encryptedString: 2c628541e2c6a7f71584f1bfd55e10a90277c30bdd83f21d3a99696e1f499ca6683da0d901e95d49e6649fed89ce7026c67b7eb9d8ed0aed63be73bbed01b5dfa9170fbde22c053cc23029b924448babed092e06576f2c2dc70ad72a114a2f11b834847aa5721472decdf5a8410ea1bb55

  const decryptedString = await decryptStringWithPrivateKey({
    privateKey: keyPrivate,
    encryptedString: encryptedString,
  })

  if (decryptedString === msg) {
    console.log('Really?')
  }
}

startHacking()