Ethereum and MetaMask Public Keys
As Ethereum developers, we’re no strangers to the intricacies of interacting with the Ethereum blockchain. Recently, several users have been puzzled by the discrepancy between the public keys displayed on their MetaMask wallet and those retrieved using the eth_getEncryptionPublicKey RPC call.
The Issue: Different Public Keys from the Same Private Key
Let’s dive into the details of what’s happening. When we use eth_getEncryptionPublicKey, it requests the encryption public key for a given Ethereum account address. However, this public key is calculated based on the private key stored in MetaMask. Here’s why:
- Private Key: The private key used to create an Ethereum wallet is unique to each individual.
- Public Key Calculation: When you retrieve your public key using
eth_getEncryptionPublicKey, you are not directly linked to your private key. Instead, it uses a different calculation method, which generates a new set of keys (public and private) based on the shared secret between your MetaMask wallet and the Ethereum blockchain.
- Shared Secret:
This shared secret is used to derive the public key from the private key.
The Solution: recoverPublicKey() vs. recoverPublicKey(). eth_getEncryptionPublicKey
To resolve this issue, you can use either of two methods:
recoverPublicKey():
* You can call recoverPublicKey() on your MetaMask wallet to retrieve the public key associated with a specific Ethereum address.
* This method provides the private key used by MetaMask and allows you to derive the public key from it.
eth_getEncryptionPublicKey(RPC):
* You can use eth_getEncryptionPublicKey as before to retrieve the encryption public key for your Ethereum account address.
* However, keep in mind that this will return a different set of keys than if you used recoverPublicKey().
Example Code: Recovering Public Key with MetaMask’s recoverPublicKey()
const web3 = require('web3');
const metaMask = new Web3(new Web3.providers.HttpProvider('
metaMask.getAccounts().then(accounts => {
const publicKey = accounts[0].getPublicKey();
// Recovering the private key using MetaMask's recoverPublicKey method
return metaMask . recoverPublicKey ( publicKey ) ;
});
Conclusion:
The discrepancy between the public keys displayed on your MetaMask wallet and those retrieved using eth_getEncryptionPublicKey RPC calls can be resolved by using either recoverPublicKey() or eth_getEncryptionPublicKey. By understanding how Ethereum addresses, private keys, and shared secrets work together, you’ll be better equipped to navigate these complex interactions.
If you have any questions or need further clarification on this topic, feel free to ask!