Yet another tool is being added to Bitcoin’s growing number of privacy solutions.Thought up at a brainstorming event attended by Bitcoin developers and privacy researchers last summer, Pay to Endpoint (P2EP) is a relatively new trick that utilizes the well-known CoinJoin mixing technique to make blockchain analysis much harder. An early version of it, called “Bustapay,” was quickly implemented by independent Bitcoin developer Ryan Havar and is being tested as of now. Meanwhile, the privacy-focused Samourai Wallet as well as JoinMarket developer Adam Gibson are working on two P2EP projects of their own, which are getting closer to deployment too.“Privacy is essential for Bitcoin,” Havar told Bitcoin Magazine. “Ideally we want to screw up [blockchain] analysis so badly, that they can't even make it.”CoinJoinTo understand P2EP, let’s first recap what CoinJoin transactions look like, and why they are (and aren’t) useful.Many normal Bitcoin transactions send coins from several addresses (inputs), because the sender’s addresses individually don’t contain enough coins needed for the payment. This is very helpful for blockchain spies, as it usually means that all inputs in a transaction belong to the same entity. It allows for address clustering.But by combining several transactions into one big transaction, CoinJoin — a privacy solution first proposed by Bitcoin Core contributor Gregory Maxwell — has the poten...
