Before the release of Bitcoin, there were a number of digital cash technologies starting with ecash technology by mathematician David Chaum in 1987, which is electronic money based on cryptographic protocols. In 1997, Adam Back developed the hashcash technology, which is a proof of work to combat spam. Between 1998-2005, Wei Dai launched the idea of decentralized encryption. Nick Szabo developed the 'bit gold' project, which is a digital currency based on decentralization using many elements that we find in Bitcoin, and this system was subjected to a strong attack.
There has been much speculation about the identity of Satoshi Nakamoto with suspects including Wei Dai and Hal Finney. There were also some rumors about the possibility that Satoshi Nakamoto was working in the European financial sector.
