Vault Construction Using Blinded Co-Signers
Developer Jonathan T. Halseth has released a prototype for a vault scheme using blinded co-signers. Unlike traditional co-signing methods, this approach utilizes a blinded version of MuSig2 to ensure signers have minimal knowledge about the on-chain movements of the funds they are securing.
To prevent signers from blindly signing malicious transactions, the proposal attaches a Zero-Knowledge Proof to the signature request. This proves the transaction complies with a pre-defined policy—in this case, the timelock of the final transaction.
The flowchart outlines four pre-signed transactions: vault_deposit, vault_recovery, unvault and unvault_recovery. During the unvaulting, the co-signer requires a proof that the transaction correctly sets a relative timelock. This ensures that in case of an unauthorized unvault, the user or a watchtower still has a window of time to reclaim the funds. A prototype implementation (GitHub) is available for testing on regtest and signet.
The author explores a potential footgun in BIP OP_CHECKTEMPLATEVERIFY (OP_CTV): Unsatisfiable UTXOs. Because OP_CTV can be used in “forwarding address contract”, which involves the problem of key-reuse. For example, a hot wallet might use an address which can automatically be moved to a cold storage address after a timeout. Reusing addresses in this way may lead to loss of funds.
The author argues that there is no significant benefit to committing to a single input, while the risks are high. He suggests that when building OP_CTV templates, it is prudent to commit to at least two inputs. Users can then craft a "secondary input" to satisfy the total amount locked in the template. A Python test (GitHub) demonstrating this recovery mechanism has been provided.
OP_CC: A Simple Introspection Opcode to Lower UTXO Consolidation Costs
Developer billymcbip proposed a new Tapscript opcode, OP_CHECKCONSOLIDATION (OP_CC). This simple introspection opcode significantly improves the space efficiency of consolidation transactions, thereby reducing the cost of UTXO Consolidation (merging multiple small UTXOs into larger ones).
Current discussions focus on the necessity of OP_CC and how it compares to the more versatile OP_CHECKCONTRACTVERIFY (OP_CCV) in terms of efficiency and implementation complexity.
QRMVL: A Modular Verification Layer for Post-Quantum Signatures
Developer Karin Eunji proposed QRMVL (Quantum-Resilient Modular Verification Layer), a soft-fork compatible verification layer designed to provide a progressive path to post-quantum security without altering current validation semantics.
QRMVL combines a hybrid LMS / SPHINCS+ signature architecture with a STARK-inspired Linear Hash Tree (LHT) optimization. Compared to standard SPHINCS+, it reduces verification latency by 57% and witness size by 48%.
The author is also advancing a Bitcoin commit-and-reveal quantum-resistant scheme. This path allows the ecosystem to gradually develop quantum-resistant vaults and covenant primitives without introducing premature trust assumptions or rushing into complex signature migrations.
Timelock-Recovery: A New Long-Term Asset Security Mechanism
Oren proposed a "Timelock-Recovery" mechanism to provide monitorable, revocable, and low-maintenance recovery/inheritance for long untouched wallets without requiring new consensus rules.
The scheme involves pre-signing a pair of transactions:
Alert/Trigger Transaction: A consolidation transaction that keeps most funds in the original wallet but moves a small amount to an "anchor address" to facilitate CPFP (Child-Pays-For-Parent) fee bumping.
Recovery Transaction: Moves BTC from the consolidated UTXO to a secondary wallet. It uses an nSequence relative timelock, giving the user time to move funds elsewhere if they notice the Alert transaction has been mined.
Proof of Buying: A Layer 2 Consensus for Proof of Work Layer 1
The Nervos community proposed Proof of Buying (PoB) as a consensus mechanism for Layer 2 networks anchored to programmable PoW chains (like CKB).
Mechanism: Miners pay Layer 1 native tokens (e.g., CKB) as a mining cost and use a VDF (Verifiable Delay Function) to compete for block production rights.
Value: PoB maintains PoW principles through tangible economic costs and creates a direct value loop: increased L2 activity drives demand for the L1 token.
SlowMist: 2025 Blockchain Security & AML Annual Report
SlowMist released its 2025 report analyzing major security incidents, APT (Advanced Persistent Threat) trends, and money laundering patterns.
Key Findings:
Higher Total Losses: 200 security incidents resulted in ~$2.935 billion in losses. While the number of incidents decreased compared to 2024 (410 incidents), the total value lost increased by 46%.
Ethereum as the Primary Targeted Ecosystem: Ethereum remained the most frequently attacked blockchain and suffered the largest losses ($254 million lost), followed by BSC and Solana.
DeFi as the Top Targeted Sector: DeFi accounted for 63% of incidents. However, Centralized Exchanges suffered massive losses from fewer incidents (12 events totaling $1.809 billion), driven largely by the ~$1.46 billion Bybit incident.
Primary Causes: Smart contract vulnerabilities (61 incidents) and compromised accounts (48 incidents) were the leading causes of loss.
The report provides a detailed breakdown of the Top 10 security incidents by loss in 2025 and highlights emerging fraud techniques that demand close attention, including:
Phishing Attacks: Phishing remains one of the most active risks, with techniques evolving far beyond traditional fake websites and forged authorization pages. Attackers now combine system commands, wallet permissions, protocol mechanisms, and even device control to execute composite attacks. Four typical patterns are highlighted: ClickFix phishing, Solana wallet ownership tampering, EIP-7702 authorization abuse, and "Fake Protection" scams.
Social Engineering: Blockchain-related social engineering showed a significant upward trend in 2025, serving as a critical entry point for phishing, malware deployment, and asset theft. These attacks manipulate trust through impersonation, emotional pressure, and information asymmetry to induce victims into high-risk actions.
Supply Chain & Open-Source Ecosystem Pollution: Software supply chain attacks remain highly active. Attackers no longer focus solely on compromising well-known libraries or core infrastructure; they increasingly target smaller open-source projects, developer tools, and dependency distribution chains. By injecting malicious code, they launch indirect, large-scale attacks on downstream users.
Other malicious attacks include browser extensions and ecosystem risks, AI-powered attacks, Ponzi schemes.
Additionally, the report summarizes 2025 Anti-Money Laundering (AML) trends, covering law enforcement and sanctions, regulatory policies, data on frozen/recovered funds, and the activities of organized cybercrime groups.
For full details, refer to the SlowMist 2025 Blockchain Security and AML Annual Report.
