This repository exists to demonstrate a point of vanilla OpenZeppelin library (read stdlib for Solidity smart contracts) and Web3 v1.0 treating signatures differently.
Ethereum signature actually comprises three numbers, r, s, v. The first two represent point coordinates,
in an ambiguous way. The ambiguity is resolved by the latter value v, which encodes what actual point on a plane
corresponds to r, s coordinates.
Ethereum Yellow Page states valid values to be 27 or 28.
Based on a tradition, for lack of better words, this number actually could be either 0/1 or 27/28.
OpenZeppelin ECDSA contract expects it to be 27 or 28. It removed support of the 0/1 values
to mitigate a replay attack some time ago.
It seems, web3 v1.0 belongs to a different tradition setting v to 0/1. In order to demonstrate that, I modified
vanilla MetaCoin Truffle box, to do ECDSA.recover of a signature prepared by web3. Hopefully, I did something wrong.
If not, this is a case of miscoordination.
1 hour later. Ok, it is not web3. My mistake was to conflate web3 and whatever manages a private key. For the present case,
Ganache is was to blame: trufflesuite/ganache#427.
The new release is soon. Looking forward to having this for real.
Sergey Ukustov sergey@ukstv.me