On Friday July 12th, 0x shut down their v2 Exchange because a flaw in the signature verification routine meant that a signature of 0x04 was treated as a valid signature for all non-smart-contract accounts. This blog post explains how this is possible.Background0x is, when grossly oversimplified, a platform which allows users to trade with other users. If Alice wants to buy 1000 ZRX for 1 ETH, Alice can submit an order through the 0x protocol. If Bob then decides that he wants to take Alice&ap...
