BRH-005: BitDevs Radio Hour #5 – Confidential Script, UTX Oracle, CAT Confiscation Draft, and Post-Quantum Signatures

Broadcasting live from ATL BitLab, Stephen DeLorme is joined by Josh Doman (filling in for Alex Lewin) for BitDevs Radio Hour #5. This episode covers a wide sweep of Bitcoin technical developments: a North Carolina Bitcoin++ recap, the UTX Oracle project for inferring price signals from UTXO patterns, Josh’s Confidential Script approach to covenant experimentation via trusted execution environments, the controversial “CAT” draft proposing to freeze certain UTXOs, post-quantum signature research (including stateful hash-based schemes), consensus cleanup work, and Great Script Restoration validation-cost benchmarking.

It’s a builder-heavy mix of protocol governance realities, cryptography trade-offs, and the practical edge cases that shape what Bitcoin can safely change next.

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Episode Summary

Stephen opens with Atlanta community updates and welcomes Josh as guest host. Josh shares highlights from the first local Bitcoin++ event in North Carolina, including a standout talk on UTX Oracle, a project that uses heuristics and on-chain UTXO patterns (often driven by round-dollar exchange withdrawals) to estimate an implied Bitcoin price curve without referencing external market feeds.

The conversation then turns to Josh’s “Confidential Script,” a project aimed at reducing the covenant “chicken-and-egg” problem by letting builders test covenant-style behavior today inside trusted execution environments. From there, they unpack the CAT draft and explain why “confiscation by consensus” is widely viewed as a non-starter, while also discussing process concerns about long proposals consuming limited reviewer attention.

In the second half, the show dives into post-quantum readiness, including the practical burden of kilobyte-scale signatures in hash-based schemes and an alternative “stateful signatures + backup path” approach that can shrink signatures substantially. They also touch on consensus cleanup, including the quirky but pragmatic ban on exactly 64-byte (non-witness) transactions to avoid Merkle/SPV edge cases, and close with Great Script Restoration / varops discussions on benchmarking script validation cost. Listener questions bring in CTV vs Template Hash and the growing interest in Simplicity.

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Topics Covered

🎉 ATL BitLab, Community Updates, and Bitcoin++ Local

• Josh Doman fills in for Alex Lewin on BRH #5
• Atlanta Bitcoin holiday party recap and year-end meetup pause
• Bitcoin++ North Carolina local edition recap
• Conference themes that emerged: mining and covenants

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📈 UTX Oracle: Estimating Price from UTXO Data

• How repeated “round dollar amount” behavior can show up as patterns in the UTXO set
• Why exchange withdrawals are a major driver of that signal
• How inscriptions/ordinals activity can distort the model (and how filtering helps)
• Why the approach could become less reliable with mainstream retail payments

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🧩 Confidential Script: Covenant Experiments via Trusted Execution Environments

• The covenant governance problem: proving demand and funding builds before consensus changes
• Using TEEs to run script evaluation and emulate covenant-like constraints today
• Positioned as experimentation tooling rather than production custody
• Mentioned compatibility targets (discussed): CTV, CAT, CSFS

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🐱 The “CAT” Draft and Why Confiscation Is a Non-Starter

• Draft proposal framing: declare certain “non-monetary” UTXOs unspendable
• Principled objections: censorship resistance and precedent-setting
• Practical objections: defining “dust” and “non-monetary” over time
• Process commentary: short idea checks vs lengthy proposals that consume reviewer bandwidth

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🧪 Post-Quantum Signatures: Size, Verification Cost, and Stateful Alternatives

• Hash-based post-quantum schemes as the most conservative cryptographic assumption set
• Signature size reality check: tens of bytes today vs kilobytes for PQ candidates
• Stateful PQ signature idea: a smaller “regular path” plus a larger recovery/backup path
• Wallet UX trade-offs: address derivation, backups, and potential address reuse pressure

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🧹 Consensus Cleanup: The 64-Byte Transaction Edge Case

• High-level overview of “consensus cleanup” work and why it targets rare edge cases
• The memorable rule: making exactly 64-byte (non-witness) transactions invalid
• Motivation: avoiding Merkle/SPV proof ambiguity

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🧾 Great Script Restoration and varops: Measuring Validation Cost

• Why validation cost is more than “block size” or “sigops”
• How opcode combinations can create high verification workloads
• Benchmarking across hardware to ground realistic cost budgets

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💬 Listener Q&A: CTV, Template Hash, and Simplicity

• CTV activation coordination discussion and timing
• Template Hash as an alternative expression of similar functionality
• Simplicity as a potential longer-term path for more expressive script with analyzable cost

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Links Mentioned

• Josh Doman’s Bitcoin++ talk (add link)
• UTX Oracle project (add link)
• CAT draft discussion post (add link)
• Post-quantum signature analysis post (add link)
• Delving Bitcoin: “324-byte stateful post-quantum signatures” (add link)
• CTV activation meeting / IRC note (add link)

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Closing Notes

Stephen wraps with thanks to listeners, notes that Atlanta meetups return in January, and encourages the audience to support the show on Fountain.