AutoMod removed the original post due to “wrongly linking an user directly in the post”. smh. Posting again.
TL;DR: Timeline of scientific papers and original ideas that ended up leading to Bitcoin.
****, **The Diffie–Hellman key exchange protocol**: This is the first known protocol to propose a private and a public key in cryptography. Before that, two parties would needed to agree in advance on which key would be used to decrypt a message. It’s the classical “knock this *tip tip top* pattern when you reach my door” we see in old movies. After the protocol, no previous agreement was needed. You can find the paper here: [https://ieeexplore.ieee.org/document/1055638/](https://ieeexplore.ieee.org/document/1055638/)
**, David Chaum’s eCash**: He published many papers about how to transfer value through the web. A full list can be found here: [https://www.chaum.com/publications/](https://www.chaum.com/publications/).
**[1980’s], The Goldwasser-Micali-Rivest Digital Signature**: With the DH protocol, you could share your public keys and the other party could decrypt your message, but there was no way for this other party to verify if the message was actually sent by you. The papers published in the 1980’s by these authors fixed that. A nice paper from them that summarizes everything can be found [here](https://people.csail.mit.edu/silvio/Selected%20Scientific%20Papers/Digital%20Signatures/A_Digital_Signature_Scheme_Secure_Against_Adaptive_Chosen-Message_Attack.pdf).
**, Adam Back’s HashCash:** The very first proof-of-work algorithm that was probably the biggest inspiration for Satoshi. You can find all the related papers here: [http://hashcash.org/papers/](http://hashcash.org/papers/)
****, **Wei Dai’s B-money concept**: Traced out the very concept of what we know today as smart contracts and exchange of value without the need of a third-party verification. Read it here: [http://www.weidai.com/bmoney.txt](http://www.weidai.com/bmoney.txt)
**, Liberty Reserve:** A centralized digital currency system based in Costa Rica. Shut down due to tax implications and money laundering for criminal uses. More info on their [Wikipedia page](https://en.wikipedia.org/wiki/Liberty_Reserve).
**, Nick Szabo’s Bit Gold:** I hardly doubt that Satoshi did not read Nick’s idea and proposal (and I’m not sure if he/she/they ever mentioned it in their communications). It’s extremely similar to what Bitcoin is. Details can be found here: [https://unenumerated.blogspot.com/2005/12/bit-gold.html](https://unenumerated.blogspot.com/2005/12/bit-gold.html)
There would be a lot more to share, because science is cumulative: Maxwell’s electromagnetism needed Newton’s calculus, Newton’s calculus needed Hasan Ibn al-Haytham’s and others’ ideas; Einstein’s photoelectric effect needed Planck’s energy quantization, which needed Clausius’s and Gibb’s works on thermodynamics, so forth and so on.
Some say that Bitcoin is a technological fraud, because it poses nothing new, i.e. all of its ideas were published before, these people forget that the theory was published in *separate papers and perspectives.* With this argument, we can pretty much say that Maxwell’s electromagnetism is a fraud. Why don’t we say that? Because it works. The same goes for Bitcoin.
Godspeed and happy 60k!
Contribuiton of user oGceaseless: Satoshi greatest contribution was to solve the Byzantine Generals Problem.