blockchain

James Mickens of Harvard gives a funny lecture at HBS's Future Assembly arguing that blockchains are a very bad idea. He covers their trust, legal and practical shortcomings for real-world problems.

Andreas Antonopoulos explains how to tell Bitcoin-style blockchains from corporate blockchain hype. He argues the goal should be de-banking everyone rather than banking the unbanked.

Anders Brownworth gives a basic visual introduction to blockchain using an interactive web demo, covering SHA256 hashes, blocks, chains, distribution, tokens and coinbase transactions.

The opening lecture of MIT's Blockchain and Money course taught by Gary Gensler, covering the course plan, the history of failed digital currencies, cryptography and what a blockchain is.

3Blue1Brown explains the math and mechanics behind Bitcoin visually: ledgers, digital signatures, proof of work and the blockchain, building up a decentralized payment system from first principles.

Tom Scott explains why electronic voting is a bad idea. Elections must be trusted by everyone and attacks on software scale in ways attacks on paper do not, so open source or blockchain fixes do not solve it.

A UC Berkeley CS 161 lecture by Nicholas Weaver on cryptocurrency and blockchains, covering how they work and the case against them. It is aimed at a computer security course audience.

WIRED has UCLA professor Amit Sahai explain zero-knowledge proofs to a child, a teen, a college student, a grad student and an expert. Each round goes deeper into the cryptography and why it matters.

Lex Fridman interviews Ethereum co-creator Vitalik Buterin about Ethereum, cryptocurrency and the future of money. The conversation also touches on technical topics such as quantum computing and mining.

A two-minute clip of Andreas Antonopoulos explaining why a 51% attack on Bitcoin would not destroy it and what such an attack would cost. It is a succinct take on mining security.

Ian Miers' Devcon4 talk on failures in on-chain privacy for Bitcoin and Ethereum. It covers attacks on transparent and decoy-based schemes, including how Monero-style privacy can be eroded over repeated transactions.

An 8-minute explainer on the Lightning Network and how it relates to Segwit, Bitcoin and Litecoin. It covers how off-chain payment channels route payments to scale blockchain transactions.

Apple security head Ivan Krstic gives a Black Hat 2016 talk on iOS security, covering HomeKit, Auto Unlock and iCloud Keychain. He explains key hierarchies and how data can stay safe even in adversarial clouds.

A short explainer on the history and mechanics of public key cryptography and the Diffie-Hellman key exchange. It uses a mixing-paint-colors analogy to show how two parties can agree on a shared secret in public.

Moxie Marlinspike's BlackHat 2011 talk examines weaknesses of SSL and the certificate authority system and proposes Convergence, a decentralized notary approach with trust agility.

Dan Olson's roughly two-hour video essay critiques NFTs, cryptocurrency, and Web3, covering their technical, economic, and ideological flaws. It is heavily sourced and ends with the advice to ask whether a project needs crypto to work.

A Google Tech Talk by Steve Weis that introduces modern cryptography and its use in practice and at Google. It covers proofs of security and security definitions and a special topic. HN commenters treat it as a talk on verifiable electronic voting.

Tom Scott explains for Computerphile why electronic voting is a bad idea, arguing that paper ballots are transparent, auditable and hard to tamper with at scale. He covers why moving voting to phones, tablets or computers undermines trust and verifiability.

Dan Olson of Folding Ideas spends months in the virtual world Decentraland and delivers a long critique of the metaverse, NFTs and DAOs, and why virtual worlds fail as places.

Mike Hearn's talk at the 2012 London Bitcoin Conference on the future of Bitcoin, new applications and rebuilding the banking system. He covers lesser-known protocol features such as contracts, escrow and scripting.

Bob Beck of OpenBSD describes the first month of LibreSSL, the fork aimed at cleaning up OpenSSL, including oddities found in the code base and why it was cleaned rather than audited cryptographically.

Kim Nilsson presents his investigation into how Mt. Gox was hacked and mismanaged, tracing the finances and the missing bitcoins. It was given at the 2017 Breaking Bitcoin meetup.

Numberphile interviews cryptographer Ron Rivest about end-to-end verifiable voting. He explains how homomorphic encryption and receipts let a voter confirm their ballot was counted without being able to prove how they voted to anyone else.

Barely Sociable presents a case that Bitcoin creator Satoshi Nakamoto is cryptographer Adam Back. It uses interview clips and circumstantial evidence, and also touches on the block size dispute.

Moxie Marlinspike's DEF CON 19 talk on the weaknesses of SSL and the certificate authority system. He explains how CA trust became a problem and proposes an alternative that removes the CA oligopoly without reducing security.

Coffeezilla gives a comprehensive history of Tether, the stablecoin issued by a company controlled by the owners of Bitfinex. He lays out accusations that it is not fully backed.

Numberphile's Dr James Grime explains the flaw in the Enigma machine, namely that a letter could never be encrypted to itself, and how that helped the Allies break the code. It touches on the Bombe and Alan Turing.

A five-minute CGP Grey explainer arguing that a phone is effectively an extension of your mind, and that any backdoor or master key into encrypted devices will inevitably be abused or leaked. It frames the encryption debate as locks that are either unbreakable or absent.

Moxie Marlinspike's Black Hat talk presenting sslstrip, which defeats SSL in practice by intercepting the http-to-https redirect.

3Blue1Brown illustrates how enormous the 256-bit search space is, showing how infeasible it is to find a hash or key by guessing and checking.

A documentary from Swan Bitcoin exploring Bitcoin's relationship with energy, featuring Lyn Alden and others, and arguing that mining is a net positive for the environment and not wasteful.

A step-by-step animated explanation of how SHA-256 works, from padding and message schedule to the compression function and final hash, with source code for the animations.

Moxie Marlinspike speaks at Next Generation Threats 2014 about the challenges of encrypted communication and how Signal addresses them. He also draws on American action movies as narrative for secure communications.

Christof Paar's university lecture introducing Galois fields and finite-field arithmetic as used in AES. It covers the mathematics behind the AES S-box.

Peter Rizun and Andrew Stone present results of tests running 1 GB blocks on a Bitcoin test network at Scaling Bitcoin Stanford. The talk argues for big-block scaling and discusses its consequences.

Dr Mike Pound of Computerphile shows how a modern laptop can crack Enigma, using a ciphertext-only attack based on an older paper. He compares it with the tooling in CrypTool.

Daniel J. Bernstein and Tanja Lange survey recent highlights in post-quantum cryptography at 35C3, covering the NIST competition, network protocol experiments, and broken candidates.

MinutePhysics explains Shor's algorithm, showing how a quantum computer factors large integers by finding the period of a number modulo N. It walks through the modular arithmetic and number theory that give the exponential speedup over classical factoring, and why this threatens encryption.

Brian Warner, author of magic-wormhole, presents the tool at PyCon 2016. He explains how a few secret words let two computers securely transfer files, covering the cryptography (NaCl, SPAKE2) and library use.

Bob Beck of OpenBSD gives a BSDCan 2014 talk on the first month of LibreSSL, the OpenSSL fork. He explains why they forked, what they removed, and examples of the problems found in the OpenSSL code base.