Latest Bitcoin TLDR Newsletters

May 5 - May 11, 2025

Joshua Doman's "Graftleaf" proposal is a significant advancement in Bitcoin's scripting capabilities, introducing a method for generalized program composition and coin delegation through a new Taproot leaf version. It aims to overcome the limitations of previous proposals by supporting complex script compositions and delegations, promising improved privacy, fungibility, and backward compatibility with existing P2TR addresses. The technical sophistication of Graftleaf is highlighted by its design to prevent security issues like replay attacks and witness malleability, emphasizing its potential for creating complex spending policies such as "vault-of-vaults" ([source](https://gnusha.org/pi/bitcoindev/0b5b560b-aa0c-4669-9621-67ccbecba516n@googlegroups.com/T/#u#m2f5da099a7ecd43f8a7495cba67f9a009ca57851)). The transition from OP_VAULT (BIP-345) to OP_CHECKCONTRACTVERIFY (CCV) marks a pivotal development in Bitcoin scripting, with CCV offering a more general and efficient approach to secure Bitcoin vaults. This evolution retains the foundational appeal of VAULT while introducing improved functionality and flexibility, setting a new benchmark for future proposals despite challenges in implementing certain security-enhancing "decorator" opcodes ([source](https://delvingbitcoin.org/t/withdrawing-op-vault-bip-345/1670)). Discussion on routing in payment networks, led by brh28, addresses liquidity uncertainty and inefficiencies in path discovery, proposing cooperative path queries to enhance routing efficiency and reduce costs. This model promotes a distributed routing landscape by enabling dynamic information sharing among nodes, improving the success rates of large payments, and minimizing reliance on comprehensive channel graphs. Despite privacy concerns, the approach offers a balanced mechanism for nodes to manage information disclosure, potentially revolutionizing payment routing in the network ([source](https://delvingbitcoin.org/t/path-queries-overcoming-liquidity-uncertainty-and-other-routing-limitations/1672)).

Apr 28 - May 4, 2025

Anthony Towns highlighted a pivotal update in the Bitcoin network where the `mempoolfullrbf` default setting was changed in version 28.0, marking a significant shift that could influence network operations and user experiences, given the considerable adoption rate of this version. This change prompts a closer examination of its implications on transaction dynamics and support requirements [source](https://gnusha.org/pi/bitcoindev/CABZBVTBupMcBbOUtLbMaEmAiWGsMwisNW+k+bTUJGsUad2=ZZg@mail.gmail.com/T/#mb7bc2785adb6d821b21cceedeb33b7f641ec580c). Antoine Poinsot alerted the community to a security advisory addressing a low-severity issue in Bitcoin Core versions prior to 29.0, underscoring the importance of adhering to updated security practices and the project’s transparent disclosure policy. This advisory, along with the detailed security disclosure policy, is essential for maintaining the integrity and trustworthiness of the software [source](https://gnusha.org/pi/bitcoindev/EYvwAFPNEfsQ8cVwiK-8v6ovJU43Vy-ylARiDQ_1XBXAgg_ZqWIpB6m51fAIRtI-rfTmMGvGLrOe5Utl5y9uaHySELpya2ojC7yGsXnP90s=@protonmail.com/T/#u#mc3e78110ae4b67757a616e3c7492ce1cc56858c1). Matthew Zipkin suggested improvements to the Bitcoin development process by proposing an intermediary step involving GitHub "discussions" to bridge the gap between mailing list discourse and pull request reviews, aiming to enhance community engagement and feedback quality. This approach seeks to mitigate disenfranchisement felt by community members not involved in initial discussions and to streamline the review process for policy changes [source](https://gnusha.org/pi/bitcoindev/2294D284-77C1-4885-9585-E591FEE4878A@sprovoost.nl/T/#m42bd7df02f781ba1c91aa1db25d309126f5382be). Victor K of StarkWare introduced ColliderVM, a protocol enabling stateful computation on the Bitcoin network, facilitating a broader range of functionalities including smart contracts and layer two bridges without relying on fraud proofs. This development marks a significant leap towards enhancing Bitcoin's computational capabilities and operational efficiency, offering a glimpse into future applications that extend beyond the current scope of Bitcoin script [source](https://delvingbitcoin.org/t/collidervm-protocol-for-computation-and-l2-bridges/1662).

Apr 21 - Apr 27, 2025

Ruben Somsen's analysis reveals a potential vulnerability in SwiftSync related to the removal of checkpoints predating 2013, which currently prevent a reorganization (reorg) back to 2010, safeguarding against certain exploits. The discussion extends to the inefficiencies of BIP30 in consensus checks and its complication for implementing alternative validation methods. Somsen proposes either enforcing a no-reorg rule between specific blocks or amending pre-checkpoint consensus rules to mitigate risks associated with reorgs and the spending of duplicated transactions. Further, Somsen outlines the indefinite activation of BIP30 until the activation of BIP34 at block height 227931, highlighting concerns over output creation that conflicts with BIP34's rules. He suggests a more efficient system that caches coinbase transaction IDs (TXIDs) to prevent duplicates, potentially enabling the sunset of BIP30. This new approach aims to ensure coinbase uniqueness up until BIP34's activation block, facilitating its activation regardless of a reorg and contributing to the ongoing dialogue among developers to improve blockchain consensus mechanisms' efficiency and security. [Read more about the discussion](https://gnusha.org/pi/bitcoindev/000201dbb7b7$7af02be0$70d083a0$@voskuil.org/T/#mc008edc5f9383e091d1c6259c798877fb79588a7).

Apr 14 - Apr 19, 2025

Gloria Zhao announces the release of Bitcoin Core version 29.0, featuring performance improvements, bug fixes, and new functionalities such as `-natpmp` for better IPv4 and IPv6 support, alongside a significant shift from Autotools to CMake in the build system, aimed at enhancing the software's development process. Users are advised to follow specific upgrade procedures based on their operating system and to consult the [official release notes](https://bitcoincore.org/bin/bitcoin-core-29.0/) for detailed information on all changes, including adjustments to P2P networking, mining, and the introduction of new RPCs to improve developer interactions with Bitcoin Core. Jonas Nick, Tim Ruffing, and Yannick Seurin introduce DahLIAS, an innovative cryptographic protocol allowing for constant-size, interactive aggregate signatures compatible with secp256k1. This advancement, detailed in their [published paper](https://eprint.iacr.org/2025/692.pdf), presents a significant step forward in reducing transaction sizes and verification costs for Bitcoin and similar applications, marking a key development in the efficiency and scalability of cryptographic practices within digital currency systems. A debate surrounding the moderation guidelines in the Bitcoin Core metadata repository has emerged, with proponents arguing for the removal of such policies citing concerns over formal governance structures potentially influencing consensus rules. This discussion, fueled by references to decentralized development philosophies and legal considerations like the Berne Convention, underscores the tension between maintaining civility within the community and adhering to the foundational principle of decentralization. The dialogue encapsulates a broader discourse on the balance between structured governance and the anarchic ethos that has historically underpinned Bitcoin's development community, as detailed in [this forum post](https://delvingbitcoin.org/t/some-problems-with-current-bitcoin-core-moderation-md/1616).

Apr 7 - Apr 13, 2025

Ruben Somsen introduces SwiftSync, a novel method that streamlines the Bitcoin blockchain validation process by using hints for unspent transaction outputs and requiring less than 100MB for validation, significantly enhancing efficiency and enabling parallel processing. This approach negates the need for a stateful UTXO set during initial block download, promising a potential 5.28x speed-up in transaction validation ([source](https://gnusha.org/pi/bitcoindev/CAPv7TjaM0tfbcBTRa0_713Bk6Y9jr+ShOC1KZi2V3V2zooTXyg@mail.gmail.com/T/#u#mc66763934f25b65ce5006f0a4dd19cd359a8b452)). Ethan Heilman discusses the integration of Post-Quantum signatures into Bitcoin, highlighting their larger size and the scalability challenge it presents. He proposes Non-interactive Transaction Compression as a solution, which could drastically reduce transaction sizes and increase Bitcoin's transaction throughput, addressing scalability and economic implications of larger PQ signatures while acknowledging the need for efficient proof construction to avoid mining centralization ([source](https://delvingbitcoin.org/t/post-quantum-signatures-and-scaling-bitcoin-with-starks/1584)). Robin Linus elaborates on the use of input-committing covenants for constructing more efficient and secure bridges in the BitVM ecosystem, leveraging CTV and CSFS to eliminate the need for presigning committees and significantly reduce transaction sizes. This advancement simplifies bridge architecture, enhances operational efficiency, and aims towards trust-minimized Bitcoin interoperability, though challenges such as potential censorship in the peg-in process remain ([source](https://delvingbitcoin.org/t/how-ctv-csfs-improves-bitvm/1591)). Lastly, zawy proposes a novel security method for cryptocurrency seed words, using mining techniques to allow users to remember fewer seed words. By splitting a nonce into seed words and a highly public random seed, the method balances remembrance with security, making unauthorized access economically prohibitive. This approach leverages computational work as a defensive mechanism, ensuring that an attacker's costs outweigh potential gains ([source](https://delvingbitcoin.org/t/hashing-to-remember-forgotten-seed-words/1597)).

Mar 31 - Apr 6, 2025

Jonas Nick's introduction of secp256k1lab heralds a pivotal advancement for cryptographic endeavors within Bitcoin's ecosystem, providing a Python library aimed at facilitating prototyping, educational purposes, and experimentation with the secp256k1 elliptic curve. Despite its designation as INSECURE for production use, secp256k1lab supports crucial features like Schnorr signatures and Elliptic Curve Diffie-Hellman (ECDH), underscoring its potential for enhancing decentralized key generation protocols within the Bitcoin Improvement Proposal (BIP) framework. The project, developed by Sebastian Falbesoner, Jonas Nick, and Tim Ruffing, encourages community engagement for further development and is accessible on [GitHub](https://github.com/secp256k1lab/secp256k1lab). Ethan Heilman brings to light the imperative for Bitcoin to integrate Post-Quantum (PQ) signatures to counteract vulnerabilities against quantum computing attacks, proposing Non-interactive Transaction Compression (NTC) or Non-Interactive Witness Aggregation (NIWA) using STARKs for efficient PQ signature transactions. This solution aims to mitigate potential scalability and centralization issues by significantly reducing the transaction size, thus preserving Bitcoin's on-chain payment functionality and decentralization. The proposed methods and their implications for Bitcoin's future are discussed in various resources, including [Bitcoin Improvement Proposals](https://github.com/bitcoin/bips/pull/1670/files) and [SNARKs and Blockchain Future](https://medium.com/@RubenSomsen/snarks-and-the-future-of-blockchains-55b82012452b). Chris_Stewart_5 discusses the vibrant debates within the Bitcoin community concerning enhancements to Script's functionality, particularly focusing on overflow handling and arithmetic opcode enhancements. This discourse, framed by initiatives like Rusty Russell's Great Script Restoration and proposals for 64-bit arithmetic soft forks, underscores the delicate balance between computational integrity and security. The community's efforts to refine script operations reflect a broader commitment to ensuring Bitcoin's scripting language remains robust against potential vulnerabilities, as detailed in discussions on [overflow handling in Script](https://delvingbitcoin.org/t/overflow-handling-in-script/1549). Ruben Somsen's proposal to expedite Bitcoin Core's Initial Block Download (IBD) phase through pre-generated hints represents a forward-thinking approach to optimizing blockchain performance. This "IBD Booster" aims to streamline the validation process, reducing resource-intensive operations by selectively adding coins to the UTXO set, thereby accelerating the IBD phase while highlighting operational limitations and areas for future research. The community is invited to contribute to this innovative project, with tools and a proof-of-concept implementation available on [GitHub](https://github.com/theStack/ibd-booster-hints-gen) and further details on the [IBD Booster branch](https://github.com/theStack/bitcoin/tree/ibd_booster_v0).

Mar 24 - Mar 29, 2025

The discussions across various platforms delve into the complexities and potential advancements within the Bitcoin ecosystem, focusing on privacy concerns, quantum computing threats, and significant software updates. /dev /fd0 highlights the privacy implications of the Payjoin protocol and the UTXO probing attack, stressing the importance of cautious engagement in Payjoin transactions due to potential privacy trade-offs ([source](https://gnusha.org/pi/bitcoindev/450755f1-84c5-4f32-abe0-67087ae884d6n@googlegroups.com/T/#u#m926660a18f3716490069656525614926386b01fd)). Meanwhile, Matt Corallo and Josh address the looming challenge of quantum computing to Bitcoin's security, proposing different approaches to safeguard the cryptocurrency, including a freeze fork and a quantum-resistant fork, alongside emphasizing Bitcoin's inherent protections and the role of community engagement in preemptive measures ([source](https://gnusha.org/pi/bitcoindev/CAJDmzYxw+mXQKjS+h+r6mCoe1rwWUpa_yZDwmwx6U_eO5JhZLg@mail.gmail.com/T/#m4b6171f7714a7942674e46bc6487a6f9aae36410), [source](https://delvingbitcoin.org/t/is-there-a-social-approach-to-the-quantum-problem/1537)). The release of Bitcoin Core version v29.0rc2 represents a pivotal moment for the platform, aiming to bolster the network's stability and reliability through community-driven testing and feedback. This update was made available by Gloria Zhao and glozow, who encourage the community's involvement in refining the software before its final release, underscoring the collaborative effort required to advance the Bitcoin Core software ([source](https://gnusha.org/pi/bitcoindev/566a1d2f-c3e7-495e-a85b-1e21f92df2d3n@googlegroups.com/T/#u#m9489b490c59f48abcd1004164685f2dcfd1b0062), [source](https://delvingbitcoin.org/t/bitcoin-core-29-0-release-candidate-is-available/1536)). Josh further explores Bitcoin's potential as the optimal unit of account to passively stabilize the macroeconomy, advocating for its adoption based on its unique attributes and the game-theoretic argument for its eventual dominance. This discussion underlines the transformative power of Bitcoin in reshaping economic stability and efficiency through a universally accepted unit of account that aligns with total wealth ([source](https://delvingbitcoin.org/t/a-game-theoretic-approach-to-bitcoin-s-valuation-in-equilibrium/1547)).

Mar 17 - Mar 20, 2025

The recent Bitcoin Improvement Proposal (BIP) by Weichu Deng introduces two new string operations, OP_ISSUBSTR and OP_ISSUBSTRVERIFY, aimed at enhancing Bitcoin script functionalities. This development marks a significant step towards reintroducing string operations in Bitcoin scripts, addressing current development challenges by facilitating on-chain string logic processing, thereby improving script functionality without compromising security. The proposal's details and its implications for Bitcoin scripting are fully documented on [GitHub](https://github.com/Weichu-Deng/bips/blob/OP_ISSUBSTR/bip-yongdong%20wu-OP_ISSUBSTR.md). Weikeng Chen's discussion highlights the integration of CSFS with CTV (CheckTemplateVerify) in signet, aiming to advance BitVM operations and reduce on-chain data overhead. This integration within the LNHANCE project is poised to enhance application development through the synergistic use of CTV and CSFS, reflecting a broader trend of technical innovation and community involvement in the Bitcoin ecosystem. Peter Todd's contribution discusses the integration of taproot annex support into Libre Relay, informed by a pull request by Joost Jager, emphasizing the standardization of transactions containing taproot annexes. This initiative underscores ongoing efforts to refine Bitcoin's protocol, with detailed criteria to mitigate transaction pinning attacks and ensure compatibility with future soft-forks, demonstrated through specific GitHub commits and [pull requests](https://github.com/bitcoin/bitcoin/pull/27926). Salvatoshi introduces the drafting of a BIP for `OP_CHECKCONTRACTVERIFY` (`OP_CCV`), a significant advancement enabling state-carrying UTXOs that support Pay-to-Taproot (P2TR) inputs and outputs. This development enhances Bitcoin's scripting capabilities, allowing for more complex contract designs, and underscores the opcode's potential for introspecting and modifying UTXOs with embedded data and rules. The comprehensive discussion on `OP_CCV` and its integration within Bitcoin's scripting language is available at [DelvingBitcoin.org](https://delvingbitcoin.org/t/op-checkcontractverify-and-its-amount-semantic/1527). Steven Roose's analysis of the Ark protocol and its utilization of CTV for creating virtual UTXOs (vUTXOs) showcases the protocol's innovative approach to transaction facilitation and ownership transfer. This use of CTV, especially within the clArk implementation, highlights the protocol's efficiency and the broader applications of Bitcoin's scripting advancements. Further exploration of the Ark protocol's integration of CTV and its implications for the Bitcoin ecosystem can be found through various resources, including an [introduction to the Ark protocol](https://ark-protocol.org/intro/vtxos/index.html).

Mar 10 - Mar 16, 2025

Sjors Provoost introduced Testnet 4 in BIP94, supported by Bitcoin Core version 28, aimed at addressing the impracticality of Testnet3, while preserving backward compatibility for users who choose to remain with the older testnet. This development reflects the Bitcoin community's commitment to enhancing testing environments for developers and exploring innovative approaches like a proof-of-work signet to improve network functionality ([source](https://gnusha.org/pi/bitcoindev/C899E966-6444-41EC-B977-96CFFCBF936A@sprovoost.nl/T/#m3c7b2c859613fc8c66511c5012274855f2b92f7c)). Martin Habovštiak discussed the security of hashed keys against quantum computing threats, proposing a Quantum Resistant (QR) signing mechanism that allows for secure transactions even after quantum computers become viable. This approach, which includes a method to secure bitcoin through QR scripts, highlights the ongoing efforts to enhance Bitcoin's security in anticipation of future quantum computing advancements ([source](https://gnusha.org/pi/bitcoindev/CALkkCJY=dv6cZ_HoUNQybF4-byGOjME3Jt2DRr20yZqMmdJUnQ@mail.gmail.com/T/#u#m5c0e99289f1ada916372eb653f7c769864aca3a9)). The Lightning Network Daemon (LND) version 0.18.0 introduced a revised sweeper subsystem that improves transaction batching and fee bumping by incorporating HTLC deadlines and budget considerations. This advancement supports more dynamic and efficient fee adjustments, enhancing security and reducing risks associated with missed deadlines or inadequate fee payments, marking a significant step forward in managing on-chain transactions for the Lightning Network ([source](https://delvingbitcoin.org/t/lnds-deadline-aware-budget-sweeper/1512)). Josh proposed a cross-input scripting capability for Bitcoin, enhancing transaction functionality by allowing additional spending criteria commitments at the time of signing. This proposal, seeking feedback for a potential soft fork, could significantly expand Bitcoin's programmability and transaction capabilities, underscoring the community's role in guiding the future of Bitcoin's scripting capabilities ([source](https://delvingbitcoin.org/t/post-signature-cross-input-scripting-using-the-taproot-annex/1520)).