Before the internet could become a place to bank or transact, it needed a way for strangers to know who they were talking to, and whether a message could be trusted.

Turing Award winners Ron Rivest, Adi Shamir, and Leonard Adleman helped invent it.

In this episode of First Principles, Rivest tells the story of how they developed RSA, the first practical public-key cryptosystem. Their breakthrough made it possible to encrypt information, verify identities, and authenticate messages across an open network without requiring participants to meet or exchange a secret in advance — laying essential groundwork for the secure internet and, decades later, blockchains.

Rivest joins Tim Roughgarden, Head of Research at a16z crypto and Professor of Computer Science at Columbia University, and Dan Boneh — Professor of Computer Science at Stanford University, a16z crypto Senior Research Advisor, and the “B” in BLS signatures — for a conversation about the origins and future of modern cryptography.

They trace the field from its early days, when most cryptographic research was classified and even the meaning of “security” had not been formally defined, through the publication of the Diffie-Hellman paper and the open problem that ultimately led to RSA. Rivest recounts the night the core idea came together, why the difficulty of factoring made the system plausible, and why no one initially knew whether it would survive sustained attempts to break it.

The conversation also explores the other cryptographic primitives that underpin blockchains and the modern internet. Rivest explains why digital signatures interested him even more than encryption, how he designed the MD family of cryptographic hash functions, and why standards such as RSA, DSA, and SHA were shaped as much by politics, patents, and government pressure as by mathematics.

Finally, Rivest shares his unusually candid views on quantum computing, post-quantum security, and the deeper theoretical possibility that P could equal NP. Either development could threaten the foundations of modern cryptography — but, as Rivest argues, cryptographers have a responsibility to prepare for even the worst-case scenarios.

Highlights

00:00 – Intro: the two problems that could break modern cryptography
01:10 – Why Ron Rivest’s work underpins the internet and blockchains
08:10 – Before public-key cryptography, there was no theory of security
11:05 – The open problem that led to RSA
13:55 – The night Ron Rivest discovered the core idea behind RSA
17:55 – Why digital signatures were the real breakthrough
19:14 – The RSA challenge — and a prediction that was off by quadrillions of years
28:33 – How government pressure shaped cryptographic standards
30:36 – Designing the hash functions that made digital signatures practical
33:26 – The Fiat–Shamir transformation, explained
38:04 – Building a cryptography company before the web existed
42:31 – Will quantum computers ever become powerful enough to break RSA?
48:02 – The cryptography securing the internet, elections, and everyday life
50:11 – What surprised Dan: Quantum giveth and quantum taketh away

About First Principles

First Principles is a special limited series from a16z crypto about the scientific roots of modern computing — especially blockchains — told through rare conversations with the pioneers who helped shape the foundational ideas behind distributed systems, consensus protocols, economics, mechanism design, cryptography, zero knowledge, and more.

People often tell the story of the Bitcoin whitepaper as if it appeared out of nowhere. But the ideas behind Bitcoin — and blockchains more broadly — come from decades of computer science, economics, mathematics, and cryptography. First Principles is a guide to that lineage, as told by the people who helped build it.

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Hear more from:

Ron Rivest: https://people.csail.mit.edu/rivest/
Tim Roughgarden: https://twitter.com/Tim_Roughgarden
Dan Boneh: https://twitter.com/danboneh

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The Story Behind RSA: The Invention That Secured the Internet (ft. Turing Award Winner Ron Rivest)

a16z crypto show

The Story Behind RSA: The Invention That Secured the Internet (ft. Turing Award Winner Ron Rivest)