“In Cryptography We Trust” According to Neal Koblitz

Professor Neal Koblitz gave a lecture on cryptography on Saturday, October 13th, 2018 in Kane Hall at the University of Washington Blockchain Expo.

Entering the presentation before Professor Koblitz’s, I spotted him early and took the opportunity to sit next to him.

We had a small chat where I was able to express my anticipation for his lecture. He genuinely seemed surprised why someone may be excited as I was to hear from the co-inventor of elliptic curve cryptography (Bitcoin’s approach to public-key cryptography).

Before I was able to muster up the courage to politely ask him to speculate on who Satoshi Nakamoto is/was/are, he took to the podium and prepared to deliver the ELI5 version of his invention, elliptic curve cryptography.

Professor Koblitz begins his lecture with Bitcoin’s slogan, In Cryptography We Trust. He announces his agenda to introduce elliptic curves, digital signature structure, and Bitcoin’s Elliptic Curve Digital Signature Algorithm. Admittedly, much of the lecture was over my head, yet I wanted to share the things I found interesting:

• Digital signatures can only be implemented using public key cryptography
• From the title, the first proposal of RSA cryptography denotes obtaining digital signatures > public-key cryptosystems
• Professor Koblitz explains Rivest, Shamir, and Adleman, did not see the importance of their discovery in public-key cryptosystems
• British equivalent of the NSA discovered RSA cryptography 5 years prior, but did not discover the RSA signature or understand the importance of their discovery
• Academic cryptographers at MIT had the foresight to realize the signature part of RSA cryptography
• Crucial property of a good signature system is non-repudiation
• Every Bitcoin participant is using the same elliptical curve. It is possible to use more than one elliptic curve, but it isn’t practical
• Like many cryptosystems, the devil is in the details and is very easy to get wrong (e.g., 2010 Sony Playstation 3 ECDSA blunder)

At this time, Professor Koblitz begins taking questions. There is a particular question that I would like to highlight pertaining to the future of quantum computing.

How will Shor’s algorithm impact elliptic curve cryptography?

• Shor’s algorithm would completely break RSA cryptography and elliptic curve cryptography
• A lot of research going on in post-quantum cryptography
• Most optimistic projection is 15 years before a quantum computer may be built
• Barring a huge breakthrough in physics, 15 years is an unrealistic projection. 30 years, perhaps
• Shor’s algorithm has never been implemented
• Nobody knows if a scaled-up quantum computer can be built
• Somebody is building a blockchain using post-quantum cryptography as a signature
• The trouble is post-quantum crypto is still being debated and remains too risky to be used as a signature
• Even if signatures can be forged 15 or 30 years from now, that does not affect the block that was confirmed much earlier. Signatures do not have to be unforgeable decades into the future. Some things do (e.g., national security secrets)

I am a full-time undergraduate student currently volunteering for Seattle’s advanced-level blockchain conference, The Token Forum. I am currently seeking a career in the blockchain space. Feel free to reach out to me via LinkedIn or Twitter.