James Lovejoy on detecting and mitigating double-spends (EP.111)
On The Brink with Castle Island
Release Date: 08/10/2020
Weekly Roundup 10/09/26 (Going Bunker Mode, classical ECC breaks, AI’s math discoveries) (EP.744)
On The Brink with Castle Island
Matt and Nic are back with more deals and news. In this episode: Is it appropriate to have AI manage your fantasy league? Quant firms are hiring “quals” Justin Drake scares everyone in crypto Did AI destroy math? Why a classical ECDSA break would be worse than a quantum one Why we lean forward hash-based signatures for post-quantum Why rotating your address doesn’t help now Is Bitcoin the “least of our concerns” if ECC breaks? Nic makes a new scientific discovery with Astra The NFL thinks that gambling should be state regulated What’s driving interest in Pokemon cards? ...
info_outline
Esther Wong (Cashi) on Making Stablecoins Spendable (EP.743)
On The Brink with Castle Island
Esther Wong, founder and CEO of joins the show. Cashi is a stablecoin spending app and cashback card with a global footprint. In this episode we discuss: Customer personas and use cases for stablecoin payments The future of tokenized equities on chain The landscape of layer one and two blockchains and how these platforms converge with global stablecoin applications Cashi’s roadmap and plans for the coming year To learn more about , visit their website and follow Esther Wong on .
info_outline
Weekly Roundup 10/02/26 (Fat Model Hypothesis, Agentic bank runs, Hester Peirce retires from the SEC, ETH 2030) (EP.742)
On The Brink with Castle Island
Matt and Nic are back with another week of news and deals. In this episode: Are OpenAI and Anthropic reenacting the Fat Protocol Hypothesis Will AI agents cause bank runs optimizing bank balances for yield? If the AI complex bursts does it take down VC? Our tribute to Hester Peirce as she retires from the SEC The SEC and CFTC publish crypto FAQs Vitalik lays out his vision for Ethereum in 2030 Quantum progress is accelerating Illinois delays their crypto transaction tax Is San Francisco better than it was?
info_outline
Weekly Roundup 09/25/26 (Post Clarity rulemaking, Sherrod Brown is back, RIP BitMEX, Coldcard white hats, is EA a cult?) (EP.741)
On The Brink with Castle Island
Matt and Nic are back with another week of news and deals. In this episode: How loud are America’s largest data centers? What’s wrong with XAI’s data center in Mississippi? The Trump admin is reportedly trying to promote dollar stablecoins Binance invests in Circle We pick up the pieces after Clarity Fairshake plans to spend $30m opposing Sherrod Brown in Ohio How AI anxiety helps the Democrats Sherrod Brown is back to haunt crypto Coinbase is listing IPOs now Are prediction markets out of step with the original vision? BitMEX finally closes its doors 52 BTC were saved from the...
info_outline
Weekly Roundup 09/18/26 (Clarity fails to advance, Caroline Ellison’s new job, AI leaking MNPI, Poland’s oil snafu) (EP.740)
On The Brink with Castle Island
Matt and Nic are back for another week of news and deals. In this episode: How is SBF like Dario? The EAs are at it again Do we need new regulation to Pace the Frontier? Can Anthropic be regulated like a bank? Are baseball cards back? Clarity fails at the final hurdle Why did Clarity fail? Stablecoin yield is still in effect The SEC and CFTC are engaging in rulemaking Circle launches Arc, their new L1 Robinhood employees get caught insider trading on Hyperliquid Caroline Ellison is back and working for a former FTX portco Can AI models leak MNPI? A Polish oil company tried to buy...
info_outline
Weekly Roundup 09/11/26 (Liquid hack, AI x-risk, Silvergate revisited, can AI leak MNPI?) (EP.739)
On The Brink with Castle Island
Matt and Nic are back for more deals and news. In this episode: We bring back his the theme music Anthropic employees think there’s a 10% chance AI destroys humanity Was Jacob Coxon astroturfed or real? Are Anthropic employees being sincere or cynical? Blockstream’s Liquid sidechain is hacked What does the Liquid hack mean for privacy coins? Hunter Biden launches the $LAPTOP memecoin IONQ says they will be able to crack ECC in two years Ex Silvergate CEO Alan Lane speaks out OpenAI offers a solution to the Navier-Stokes problem Can insider information leak through AI...
info_outline
Weekly Roundup 09/04/26 (HuggingFace hack breaks containment, Hyperliquid onshoring, RSA260 factored, is the stablecoin sandwich cheaper?) (EP.738)
On The Brink with Castle Island
Matt and Nic are back for another week of news and deals. In this episode: We determine the winner of the bad boys theme song competition Dwarkesh ignites controversy with his OpenAI hack recap What actually happened with OpenAI and Huggingface? Gwern’s and Matt Huang’s short story competition Will AI make us dumb? 200m Americans KYC data has been hacked Prediction markets lawsuit heading to SCOTUS? Robinhood Chain is taking off Strategy is buying Bitcoin again Should Members of Congress be paid more? Cronos suffers a defi hack Revolut gets a bank charter Is the stablecoin sandwich...
info_outline
Guy Young (Ethena) on Digital Financial Markets (EP.737)
On The Brink with Castle Island
Wyatt sits down with Guy Young, founder of Ethena, for Guy's third appearance on the pod. In this episode: What has driven Ethena's success and durability? Where is there demand for other yield assets? Where is capital coming from? Is full onchain portfolio construction possible today? Why tokenize financial products at all? Who are the eventual winners? How is Ethena positioning to an evolving onchain yield landscape?
info_outline
Weekly Roundup 08/28/26 (BankChain alliance, Goat grazing hedges, SHRINCS, is maximalism over?) (EP.736)
On The Brink with Castle Island
Matt and Nic return for another week of deals and news. In this episode: Matt and Nic consider candidates for the new bad boys intro music 39 state banking associations form the BankChain alliance Blockstream researchers proposed SHRINCS, a PQ signature scheme for Bitcoin How much should depositors care about bank credit risk? Kalshi hosts a prediction market on goat grazing regulation Are trading bot agents getting good? Blockstream proposes SHRINCS for Bitcoin Zcash hits an 8-year high Treasury designates anyone helping Iran’s crypto sector AI watermarking Bad boys theme song...
info_outline
Weekly Roundup 08/21/26 (SALT Wyoming, SEC’s Reg Crypto, Tether’s big 4 audit, Crypto Privateers) (EP.735)
On The Brink with Castle Island
Matt and Nic return for another week of news and deals. In this episode: The boys review SALT Wyoming in Jackson Hole Why did Stripe buy Openrouter? Stripe says we have entered the Singularity People are upset about data centers The SEC proposes Reg Crypto governing token issuance The CFTC convenes a crypto roundtable in Washington FASB proposes treating stablecoins as cash equivalent under GAAP World Liberty gets an OCC charter Trump should divest his WLF tokens to push Clarity through Saylor wriggles out of another jam Tether passes a big 4 audit The White House issues a “crypto...
info_outlineJames Lovejoy, recent MEng MIT grad and former graduate researcher at the MIT Digital Currency Initiative, joins the show to talk about his masters thesis and associated project focusing on detecting double-spends in proof of work cryptocurrencies. Previously, little data was collected in a systematic way to detect double-spends and reorganizations across many cryptocurrencies. James' project sheds light on previously unknown security properties of PoW. In this episode:
- How James came to work on Vertcoin
- Why James thinks ASIC resistance is valuable
- James' blockchain monitoring project and why it matters
- Why reorgs are challenging to detect
- Why investigating the economic damage of reorgs is difficult
- How James noticed a 51% attack in progress on Vertcoin and intervened to save Bittrex money – and how this can be replicated
- Why understanding Nicehash is critical to detecting and dealing with 51% attacks
- James' critiques of dominant theoretical models of PoW security
- How James found reorgs and counterattacks happening on BTG in real time
- Why exchange processes like KYC might actually help protect blockchains from reorgs
- How permissionless trading and leverage makes certain blockchains more vulnerable to attacks
- Rules of thumb for confirmation requirements for exchanges
- The issue with calling coins "Nicehash-able" – and why it's likely a lowball
- How exchanges can proactively mitigate the risk of 51% attacks and what they should be targeting
- How BTG developers finally defeated deep reorgs
- Whether James is confident in the long-term prospects of PoW
- Whether James still believes in GPU mining
Content referenced in this episode
- James Lovejoy, An Empirical Analysis of Chain Reorganizations and Double-Spend Attacks on Proof-of-Work Cryptocurrencies
- Raphael Auer, Beyond the doomsday economics of “proof-of work” in cryptocurrencies
- Eric Budish, The Economic Limits of Bitcoin and the Blockchain
- Hasu, Prestwich, and Curtis, A model for Bitcoin's security and the declining block subsidy
- Carlsten, Kalodner, Narayanan, Weinberg, On the Instability of Bitcoin Without the Block Reward
- Moroz, Aronoff, Narula, Parkes, Double-Spend Counterattacks: Threat of Retaliation in Proof-of-Work Systems
- Judmayer et al, Pay-To-Win: Cheap, Crowdfundable, Cross-chain Incentive Manipulation Attacks on Cryptocurrencies
- Liao and Katz, Incentivizing Blockchain Forks via Whale Transactions
- James Lovejoy and David Vorick, ASICs and cryptocurrencies: benefits and drawbacks [debate]
- Nic Carter, It's the settlement assurances, stupid [blog]
- Elaine Ou, Cryptocurrency Deals can Always be Erased, for a Price [article]