bitcoin (P2P electronic cash system) Bitcoin is a free open source peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending. Bitcoin Core connects to the Bitcoin peer-to-peer network to download and fully validate blocks and transactions. zeromq is an optional dependency (autodetected). Note: This package conflicts with bitcoin-knots and both cannot be installed at the same time.