I use contract verify signature, but the address is not correct?

[wufeiafei]

hi,
I use web3swift method "Web3Signer.signPersonalMessage" make a signature, then I use the contract method "validate", but the result is not correct, the address is different with the signature address.
this is my contract:

pragma solidity ^0.4.17;

contract BBQ {

//验签数据入口函数
function validate(uint8 v,bytes32 r,bytes32 s,uint number) view returns (address,bool){

    string memory message = uint2str(number);
    string memory lengths = uint2str(bytes(message).length);
    string memory prefix = strConcat("\u0019Ethereum Signed Message:\n",lengths);
    bytes32 data = sha3(bytes(prefix),bytes(uint2str(number)));
    bytes32 prefixedHash = sha3(data);
    address endecodedAddress = ecrecover(prefixedHash, v, r, s);

    return (endecodedAddress,msg.sender == endecodedAddress);
}

function uint2str(uint i) internal pure returns (string){
    if (i == 0) return "0";
    uint j = i;
    uint length;
    
    while (j != 0){
        length++;
        j /= 10;
    }
    
    bytes memory bstr = new bytes(length);
    uint k = length - 1;
    
    while (i != 0){
        bstr[k--] = byte(48 + i % 10);
        i /= 10;
    }
    return string(bstr);
}

// 连接两个string
function strConcat(string _a, string _b) internal returns (string){
    bytes memory _ba = bytes(_a);
    bytes memory _bb = bytes(_b);

    string memory abcde = new string(_ba.length + _bb.length);
    bytes memory babcde = bytes(abcde);
    uint k = 0;
    for (uint i = 0; i < _ba.length; i++) babcde[k++] = _ba[i];
    for (i = 0; i < _bb.length; i++) babcde[k++] = _bb[i];

    return string(babcde);
}

}

and this is my swift code:

======
pls, help me check it?

[shamatar]

I’ve pushed a test into “developer” branch, it gives an idea of how to get a signature, get V, R, S from it and test it locally. I’ve also separately tested it with ethereumjs-util and got the same result

[shamatar]

I expect to also deploy a contract on Rinkeby to cross-verify it

[shamatar]

Hello @wufeiafei

I've tested everything, it worked as expected.

Here is a solidity contract for ECRecover

pragma solidity ^0.4.19;

import {Conversion} from "./Conversion.sol";

contract ECRecover {
    using Conversion for uint256;
    bytes constant PersonalMessagePrefixBytes = "\x19Ethereum Signed Message:\n";
  
  constructor() public {
      
  }
  
  function hashPersonalMessage(string _message) public pure returns (bytes32 hash) {
      uint256 length = bytes(_message).length;
      hash = keccak256(PersonalMessagePrefixBytes, length.uintToBytes(), _message);
      return hash;
  }
  
  function recoverSigner(string _message, uint8 v, bytes32 r, bytes32 s) public pure returns (address signer) {
      bytes32 hash = hashPersonalMessage(_message);
      if (v < 27) {
          v = v + 27;
      }
      signer = ecrecover(hash, v, r, s);
      return signer;
  }
}

pragma solidity ^0.4.20;

library Conversion {

    function uintToBytes(uint256 self) internal pure returns (bytes memory s) {
        uint maxlength = 100;
        bytes memory reversed = new bytes(maxlength);
        uint256 i = 0;
        while (self != 0) {
            uint256 remainder = self % 10;
            self = self / 10;
            reversed[i++] = byte(48 + remainder);
        }
        s = new bytes(i);
        for (uint256 j = 0; j < i; j++) {
            s[j] = reversed[i - 1 - j];
        }
        return s;
    }
}

In test you can also find an example of how to properly parse a signature and pass it to the contract in the

func testPersonalSignatureOnContract()

Merged in #66

Sincerely, Alex

[wufeiafei]

hi, I use method "SECP256K1.unmarshalSignature()", show the error "Use of unresolved identifier 'SECP256K1'".
And I has import import web3swift、BigInt、Result、secp256k1_ios and CryptoSwift。

====
what can I do?

[wufeiafei]

I test your exapmle， the result is ok。
Then I deploy your solidity contract for ECRecover in my private chain， the result is not ok。 I can not get the same address.

this is my code:

this is logs:
Test Case '-[web3swift_iOS_Tests.web3swiftTests testPersonalSignatureOnContract2]' passed (2.364 seconds).
Test Case '-[web3swift_iOS_Tests.web3swiftTests testPersonalSignatureOnContract3]' started.
sender:
EthereumAddress(_address: "0x0b20a195a259eea6fcc644f272c2111141c76d29", type: web3swift_iOS.EthereumAddress.AddressType.normal)
EthereumAddress(_address: "0x0b20a195a259eea6fcc644f272c2111141c76d29", type: web3swift_iOS.EthereumAddress.AddressType.normal)
3 signRes:
Optional(65 bytes)
V = 1
R = b19f774ad98eaf276d2a52d0a4ac5e09f43cf8a1166fe70583a72d0668abb108
S = 151d43a92967ce6551739579f306a49d9ccf1f9bb76a4aaa44134bfc795b7dd4
Personal hash = a1de988600a42c4b4ab089b619297c17d53cffae5d5120d82d8a92d0bb3b78f2
3 hashPersonalMessage:
.success(["hash": 32 bytes, "0": 32 bytes])
/Users/kevin/Documents/study/web3/web3swift/web3swiftTests/web3swiftTests.swift:2439: error: -[web3swift_iOS_Tests.web3swiftTests testPersonalSignatureOnContract3] : XCTAssertTrue failed -
.success(["0": web3swift_iOS.EthereumAddress(_address: "0x0000000000000000000000000000000000000000", type: web3swift_iOS.EthereumAddress.AddressType.normal), "signer": web3swift_iOS.EthereumAddress(_address: "0x0000000000000000000000000000000000000000", type: web3swift_iOS.EthereumAddress.AddressType.normal)])
/Users/kevin/Documents/study/web3/web3swift/web3swiftTests/web3swiftTests.swift:2451: error: -[web3swift_iOS_Tests.web3swiftTests testPersonalSignatureOnContract3] : XCTAssertTrue failed -
Test Case '-[web3swift_iOS_Tests.web3swiftTests testPersonalSignatureOnContract3]' failed (0.185 seconds).
Test Suite 'web3swiftTests' failed at 2018-04-19 16:32:22.487.
Executed 3 tests, with 2 failures (0 unexpected) in 2.551 (2.558) seconds
Test Suite 'web3swift-iOS_Tests.xctest' failed at 2018-04-19 16:32:22.490.
Executed 3 tests, with 2 failures (0 unexpected) in 2.551 (2.562) seconds
Test Suite 'Selected tests' failed at 2018-04-19 16:32:22.491.
Executed 3 tests, with 2 failures (0 unexpected) in 2.551 (2.566) seconds
Program ended with exit code: 1

[shamatar]

Hello @wufeiafei

I've exposed function unmarshalSignature and marshalSignature as a part of Web3.Utils.

[wufeiafei]

I test your exapmle, the result is ok。
Then I deploy your solidity contract for ECRecover in my private chain， the result is not ok。 I can not get the same address.

[wufeiafei]

Thank you very much.
I konw the reseason why the address is different.
the contract signature use hash 2 times, but web3swift hash only one time.
I has add the method "signPersonalMessage2Hash" and "personalECRecover2Hash", and pull requests.