Recover Signed Messages

[dternyak]

First off - thanks a ton for your work on this! Getting tooling around EIP-712 is going to be critical for it to be adopted so I applaud this effort!

I wanted to see if you had any intention of implementing recovery / verification for EIP-712, so that you can verify signed messages, e.g. where they are generated on the client and sent to a backend.

[rmeissner]

I assume you are talking about something like signTypedData and recoverTypedSignature in https://github.com/MetaMask/eth-sig-util

I was planning adding similar methods as provided by the js version. Currently we only use the hash generation in the libs for the Gnosis Safe Relay:

1. We generate the hash for our transaction (https://github.com/gnosis/gnosis-py/blob/master/gnosis/safe/safe_service.py#L455)
2. Use ethereum.utils to recover (https://github.com/gnosis/gnosis-py/blob/master/gnosis/safe/ethereum_service.py#L146)

So the idea would be to add a method for this and a method to generate the signature, correct?

[dternyak]

Exactly!

…

On Sat, Sep 15, 2018 at 8:28 AM Richard Meissner ***@***.***> wrote: I assume you are talking about something like signTypedData and recoverTypedSignature in https://github.com/MetaMask/eth-sig-util I was planning adding similar methods as provided by the js version. Currently we only use the hash generation in the libs for the Gnosis Safe Relay: 1. We generate the hash for our transaction ( https://github.com/gnosis/gnosis-py/blob/master/gnosis/safe/safe_service.py#L455 ) 2. Use ethereum.utils to recover ( https://github.com/gnosis/gnosis-py/blob/master/gnosis/safe/ethereum_service.py#L146 ) So the idea would be to add a method for this and a method to generate the signature, correct? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHf02YlZY9uVV2wf-r2rtN8e3uWsD67Dks5ubQCPgaJpZM4WqOTS> .

[rmeissner]

I can add that (I don't have time next week, but I should manage the week after)

[dternyak]

Much appreciated, thanks for the helpful links!

…

On Sat, Sep 15, 2018 at 10:58 AM Richard Meissner ***@***.***> wrote: I can add that (I don't have time next week, but I should manage the week after) — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHf02QZEWx2znj5xuiVuNExnyWKPjdhZks5ubSO7gaJpZM4WqOTS> .

[rmeissner]

@dternyak I added a sign_typed_data(data, private_key) method, a recover_typed_data(data, v, r, s) and some helper methods. Let me know if there are any questions ;)

[dternyak]

Amazing! Thank you so so much. I'm blocked by this on a project I'm working on, so I'm super appreciative on the quick changes.

Unfortunately, I've realized that that there appears to be multiple revisions of EIP-712, with recover_typed_data targeting an older revision that isn't compatible with MetaMask's signing format targeting the newest revision.

The newer revision has a format like so:

[
    {
        "type": 'string',
        "name": 'Message',
        "value": 'Hi, Alice!',
    },
    {
        "type": 'uint32',
        "name": 'A number',
        "value": '1337',
    },
]

That decision seems to have been made here: MetaMask/metamask-extension#4803 (comment).

My method for generating the signed message is via MetaMask, which uses the newer revision compared to the python based message signing that was in your linked examples.

I've been able to confirm eth-sig-util's recoverTypedSignature works with MetaMask's message signing.

So, I think that to get this working with the newest revision, we'll need to port this as well.

For reference, this is how I'm generating the signed message with MetaMask today:

  async signMessage() {
    console.log('AM SIGNING MESSAGE');
    const { accounts, web3 } = this.props;
    const from = accounts[0];
    console.log(from)
    const msgParams = [
      {
        type: 'string',
        name: 'Message',
        value: 'Hi, Alice!',
      },
      {
        type: 'uint32',
        name: 'A number',
        value: '1337',
      },
    ];

    /*  web3.eth.signTypedData not yet implemented!!!
     *  We're going to have to assemble the tx manually!
     *  This is what it would probably look like, though:
      web3.eth.signTypedData(msg, from) function (err, result) {
        if (err) return console.error(err)
        console.log('PERSONAL SIGNED:' + result)
      })
    */

    console.log('CLICKED, SENDING PERSONAL SIGN REQ');
    const params = [msgParams, from];
    console.dir(params);
    const method = 'eth_signTypedData';

    web3.currentProvider.sendAsync(
      {
        method,
        params,
        from,
      },
      (err, result) => {
        if (err) return console.dir(err);
        if (result.error) {
          alert(result.error.message);
        }
        console.log(result.result)
      },
    );
  }

I'd be happy to take a shot at porting the newest recover myself, and I really appreciate all the work you've done here already.

I'll check back tomorrow to see if you've had a chance to mull over this wall of text, and I'll also attempt to add the new recover methods if you agree with my analysis here. I'm pretty new to EIP-712, so I wouldn't be surprised if my understanding of the spec (and it's multiple revisions) is incorrect.

[rmeissner]

I am actually running against the latest tests of the sig utils of meta mask. eth_signTypedData still points to an older version of signTypedData that is currently supported in metamask.

See MetaMask/metamask-extension#4803 (comment)

Only once that PR is merged you will be able to make use of the new EIP712 standard by using eth_signTypedData_v3

To recover from that you need to use https://github.com/MetaMask/eth-sig-util/blob/master/index.js#L318