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The Day Cryptography Changed Forever<br>January 6, 2020<br>ContentsIntro: The Day Cryptography Changed Forever<br>Part I: How David Chaum’s eCash Spawned a Cypherpunk Dream<br>Part II: Hashcash or How Adam Back Designed Bitcoin’s Motor Block<br>Part III: If Bitcoin Had a First Draft, Wei Dai’s B-Money Was It<br>Part IV: With Bit Gold, Szabo Was Inches Away From Inventing Bitcoin<br>Part V: How Hal Finney’s Quest For Digital Cash Led To RPOW (And More)

This article by Steven Ellis was published in his Medium blog.<br>Contribute.

On 1 August 1977, Scientific American, a popular science magazine, released its monthly publication, as it had been doing since 1921. It contained an interesting mix of maths, science, engineering, biology, mechanics, geography and other such content.<br>Appearing near the end of the publication on page 120, was a short article by popular mathematician Martin Gardner entitled ‘Mathematical Games’.<br>In it, he described a ‘new kind if cypher that would take millions of years to break’.<br>The new form of cryptography, titled RSA after its inventors Ron Rivest, Adi Shamir and Leonard Adleman, was, the author claimed, about to herald a new era in cryptography.<br>As it turned out, he was spot on with his prediction.<br>The August 1977 edition of Scientific American.

What the world needs is …. trustless encryption<br>Prior to 1977, cryptography had been dominated by stream cyphers, and in particular the one-time pad.<br>The one-time pad is a random sequence numbers letters or bits, which, when combined with an original message, creates a pseudo random sequence.<br>Without knowing the one-time pad, it’s impossible to de-cypher the encrypted message. But if you do know the key, it’s a simple task to extract the original message from the encryption.<br>Maths theory shows that stream cyphers and one-time pads are the safest and most secure form of cryptography. However, using such a form of encryption comes with fairly onerous and unwieldy implementation requirements.<br>The now-famous article by Martin Gardner about RSA public key encryption, in the August 1977 edition of Scientific American.

Firstly, the key can only be used once (since using the same key on two different message immediately breaks the cipher), and secondly the key must always be as long as the original message.<br>This implies that two parties who wish to communicate securely through the use of a one-time pad, need to find a way of sharing the key with each other prior to communicating with it.<br>If such parties don’t know each other beforehand, or are separated by great distance or time, this poses a logistical problem: they somehow need to share keys with each other, before encrypted communication can take place. Moreover, if these parties somehow find a way of securely passing each other these keys (via private courier, registered mail, nuclear submarine etc.), it begs the question: why not just use that channel to communicate and bother with encryption at all?<br>A digital storm is brewing…<br>Against this backdrop, if you had gazed upon the digital landscape back in 1977, you would have seen a giant tidal wave starting to form on the distant horizon. This tidal wave was the coalescing of computer & networking hardware, software and protocols, which in time would form the Digital Revolution we experience today.<br>Many of the key components of modern computing and networking had already been discovered or invented, and were waiting for the right conditions to gain mass adoption.<br>The ARPANET (a distributed packet-switched network & the precursor to the modern internet) already existed and was in use at various corporate and academic locales. TCP (transmission control protocol, the connection-oriented protocol used by the internet) and FTP (file transfer protocol, used for the transfer of computer files between a client and server on a network) had also both already in use. Various forms of one-to-one electronic messaging such as FTPmail and Mail Protocol (which would evolve into email using SMTP in the 80s) had been invented, and were in use to send mail messages across the ARPANET. In 1965, Gordon Moore, then CEO of Intel, predicted a doubling every year in the number of components per integrated circuit (which he revised in 1975 to a doubling every two years). His prediction became known as Moore’s Law, and promised continuous and sustained advancements in digital electronics and hardware.<br>Computer companies like Intel, IBM, SAP & Honeywell were already well established. Two years earlier, two young entrepreneurs had incorporated a company in Albuquerque, New Mexico, to develop and sell BASIC interpreters for the Altair 8800. And one year prior, another young entrepreneur co-founded a company in his childhood home on Crist Drive in Los Altos, California. The companies were Microsoft and Apple respectively.<br>In short, software and hardware were ready for wide-scale and all-pervasive adoption.<br>But on the networking side, it lacked one crucial component: trustless...