ERC-7673: Distinguishable base256emoji addresses

ERC-7673 is a draft Ethereum standard, authored by William Morriss, proposing that account addresses be depicted and entered as strings of 20 emoji using a base256emoji encoding instead of hexadecimal. The proposal argues that humans often fail to distinguish long hexadecimal strings, especially when they match at the beginning and end, and that this is exploited by spoofing attacks that have misled tens of thousands of ether and other tokens. Under the standard, user interfaces would be required to display addresses as base256emoji and accept them as input, and would be encouraged to recognize strings of exactly 20 valid emoji as addresses. The draft states that each emoji maps to one byte, so addresses use half as many characters, and that the encoding can be transcoded to and from hexadecimal.