-In the beginning of the 1990`s he was writing about Digital currency.
-The Creator of the Reusable Proofs of Work system in 2004.
-A cypherpunk that developed the first secure version of PGP 2.0
-Skilled in the programming language C and software developer and cryptography expert
-He was the second user of the bitcoin project. Was in contact with Satoshi Nakamoto on the cryptography mail list.
-The first transaction of Bitcoin currency, in block 170, was made between Satoshi Nakamoto and Hal Finney.
-Identified a double-spending attack within the bitcoin network named after him: Finney Attack
Unfortunately in the end of 2009, Hal Finney was diagnosed with Amyotrophic Lateral Sclerosis.Even when he was paralyzed, Hal Finney continued developing the bitcoin project. He began working on an experimental piece of code named bcflick, which used Trusted Computing to strengthen bitcoin wallets.
Literature written by Hal Finney
Detecting Double Spending - October 15, 1993
Digital Cash & Privacy - August 19, 1993
Reusable Proofs of Work - August 15, 2004 PGP Web of Trust Misconceptions - March 30, 1994
Bitcoin and Me - March 19, 2013 RPOW