James Lovejoy on detecting and mitigating double-spends (EP.111)
On The Brink with Castle Island
Release Date: 08/10/2020
Weekly Roundup 08/07/26 (Coldcard hack continues, Ethereum mulls an issuance tweak, ai16z winds down, Clarity deadline looms) (EP.733)
On The Brink with Castle Island
Matt and Nic are back with more news and deals. In this episode: Why the Coldcard hack is worse than some major exchange and DeFi hacks What the Coldcard hack told us about the need for open weight models Is self custody over? MSTR sells more Bitcoin An FBI agent steals $1m in crypto NY state sues Kalshi Ethereum considers another change to issuance Ethereum needs to resist the urge to change monetary policy ai16z’s Eliza winds down the merit of reading sci fi The cofounder of Sui leaves for Anthropic Will Anthropic keep the discoveries to themselves? The WSJ gets it wrong on Clarity ...
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Weekly Roundup 07/31/26 (Situational Awareness collapse, Coldcard exploit, latest on CLARITY, Visions of Bitcoin 8 years on) (EP.732)
On The Brink with Castle Island
Matt and Nic are back for another week of news and deals. In this episode: What the novel Hyperion tells us about AI doom Situational Awareness liquidates most of its public book after a sharp AI selloff Will Leo have a second act? Why has AI been selling off? Over 1000 BTC stored in Coldcard wallets were stolen due to bad entropy Where does self-custody go from here? What happened with Coldcard? Political winds are shifting against crypto as midterms loom Strategy continues to strengthen its balance sheet with MSTR common sales An ice cream shop in CA is hedging the weather with Kalshi...
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Weekly Roundup 07/24/26 (BTC Security Consortium, Genesis’ Terra trade, DAT departures, Farewell to BitMEX, Network State drama) (EP.731)
On The Brink with Castle Island
Nic and Matt are back for another week of news and deals. In this episode: The Fat Model Thesis Are OAI and Anthropic in real trouble with Kimi? The Bitcoin Security Consortium is announced to tackle quantum risk Galaxy announces their Quantum Readiness Initiative Clarity is beleaguered in Washington Polymarket and Kalshi keep feuding The SEC settles with Coinbase over Gensler’s lost text messages We uncover some new documents revealing that Genesis inadvertently kicked off the UST depeg Jack Mallers leaves the XXI Capital DAT Movement Labs declares bankruptcy BitMEX finally winds...
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Weekly Roundup 07/17/26 (Teleprompter insider trading, the AI DeFi apocalypse fizzles, NY’s datacenter ban) (EP.730)
On The Brink with Castle Island
Matt and Nic are back with the deals and news of the week. In this episode: Nic licks his World Cup wounds Do Bitcoin Treasury strategies make sense? Trying to make sense of Saylor’s “bitcoin rating” Trump’s teleprompter operator has been trading on what Trump is going to say in his speeches Why do people keep insider trading on prediction markets? Clarity Act odds are trickling down Strategy shores up their balance sheet Is the Bitcoin cycle finally turning? Stripe bids for Paypal The AI DeFi apocalypse didn’t happen Kathy Hochul’s AI datacenter moratorium Why is Anthropic...
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Weekly Roundup 07/09/26 (BonkDAO exploit, Choke Point 2.0 extended to audit firms, Kraken v Mazars) (EP.729)
On The Brink with Castle Island
Matt and Nic are back with another week of news and deals. In this episode: Strategy sells $216m worth of BTC Where does Strategy go from here with STRC? Kalshi’s case faces the ban of sports contracts in NY TeraWulf signs a massive lease with Anthropic BonkDAO’s legal hack Vanguard hires a head of digital assets Kraken wins arbitration against Mazars for de-auditing them in 2022 Vitalik lays out a new four year plan Polymarket’s 5 minute BTC markets are being manipulated Content mentioned:
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Weekly Roundup 07/03/26 (OpenUSD announced, Binance leaves the EU, Strategy’s new framework) (EP.728)
On The Brink with Castle Island
Matt and Nic are back with another week of news and deals. In this episode: Saylor releases Strategy’s “Digital Credit Capital Framework” MSTR stabilizes for now though STRC is still discounted Is Saylor transitioning MSTR into a Bitcoin hedge fund? Is Strategy doing anything tricky with their mNAV calculation The OpenUSD consortium is announced Is the Tether and Circle duopoly broken? Can stablecoin consortiums work? What could cause OpenUSD to fail? Trump's 2025 diclosures include a lot of crypto Binance leaves the EU for now The K-pop DAT ends its digital asset...
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Weekly Roundup 06/26/26 (Quantum EOs, STRC's selloff, more MSTR) (EP.727)
On The Brink with Castle Island
Matt and Nic are back for another week of news and deals. In this episode: Our recording snafu STRC's depeg explained Saylor's path forward Why Strategy's issue is the converts Polymarket's questionable marketing Trump's Quantum EOs
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Weekly Roundup 06/19/26 (STRC under pressure, Illinois’ crypto tax, Open weight AI vs the AI boom) (EP.726)
On The Brink with Castle Island
Matt and Nic are back for a week of news and deals. In this episode: The Tartan Army takes over Boston Europeans are shocked that American infrastructure works STRC falls into the low $80s STRC’s liquidation cascade mechanics What are Saylor’s options now? Is the US right to put the brakes on Fable? Will open weight models puncture the AI boom? Are we living in a vulnerable world? Kristin Gillebrand’s son raises $30m for a perps exchange Make sure your tokenized equity provider has the equity Why aren’t publishers doing pay per content Content mentioned: Nick Bostrom, ...
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Weekly Roundup 06/12/26 (Strategy survives, Zcash Orchard bug, the thin model hypothesis) (EP.725)
On The Brink with Castle Island
Matt and Nic are back with a new week of news and deals. In this episode: Spanish soccer club Osasuna hedges their relegation on Kalshi Strategy shocks people by buying the dip Is Strategy sacrificing MSTR to save STRC? Saylor bolsters his cash position What factors are dragging on the BTC price? Zcash fixes a scary inflation bug SBF formally applies for a Presidential pardon The CFTC proposes banning a subset of prediction market contracts Polymarket thinks that Kalshi is spying on them European fans in America for the World Cup are discovering Buc-ees The DATs are struggling Hester...
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Omid Malekan (Columbia Business School) on Private Money, Financial Systems, and Crypto in Geopolitics (EP.724)
On The Brink with Castle Island
Wyatt sits down with Omid Malekan, a Professor at Columbia Business School, author of several books, and "Explainer-in-Chief" of blockchain technology. In this episode, Wyatt and Omid discuss: Why do stablecoins carry a persisent sense of being "dangerous" or "ungovernable? Are stablecoins truly private money? How do we define private money? Who owns our current banking and payment systems? Why do banks vocally oppose stablecoins? Who will own and control digital money networks? Are blockchains the right medium for digital finance over the long term? Is digital trust a problem?
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]