• Falcon Post-Quantum Signatures Integrated into Bitcoin Core and Performance Benchmarks
• BTC L2 Citrea Mainnet Launch: Introducing the Clementine Bridge Based on BitVM2 and ctUSD Stablecoin
• The First Permissionless BTC-ADA Bridge, BIFROST, Coming Soon
• BLISK Framework: New Complex Boolean Logic Encoding for Optimized Bitcoin Authorization
• Reducing PoW Dependence on Mempool and Consensus Time via Compressed Blocks and Delayed Verification
• OptiBridge: Trustless, Low-Cost Bridge Between Lightning Network and Ethereum

§Falcon Post-Quantum Signatures Integrated into Bitcoin Core and Performance Benchmarks

Falcon is a lattice-based post-quantum digital signature scheme, notable for its relatively small signature and public key sizes, as well as fast signing and verification times.

The code here demonstrates the integration of Falcon-512 into Bitcoin Core as a soft fork, along with benchmark tests and comparisons with traditional ECDSA. The results highlight Falcon’s advantages over currently selected post-quantum signature algorithms like SPHINCS+ and ML-DSA, which face significant time and space constraints.

§BTC L2 Citrea Mainnet Launch: Introducing the Clementine Bridge Based on BitVM2 and ctUSD Stablecoin

Citrea has officially launched its mainnet and issued a native stablecoin, ctUSD. The core component is the Clementine Bridge, which maps Bitcoin (BTC) to on-chain equivalent assets (cBTC) for use in DeFi applications.

The bridge’s security model relies on BitVM2 combined with ZK/optimistic verification. It only requires one honest participant to ensure asset security and does not rely on fully trusted custodians or multisig parties.

Citrea’s native stablecoin ctUSD is issued via MoonPay and built on the M0 stablecoin infrastructure, designed to meet institutional-grade compliance. It aligns with the upcoming GENIUS Act guidelines.

§The First Permissionless BTC-ADA Bridge, BIFROST, Coming Soon

FluidTokens announced that BIFROST, the first bridge connecting Bitcoin and Cardano, is in its final development stage. The bridge enables Bitcoin to be used within Cardano’s decentralized finance ecosystem, supports atomic swaps, and directly facilitates cross-chain liquidity.

BIFROST’s innovation lies in leveraging Cardano’s existing security infrastructure—Stake Pool Operators (SPOs)—to safeguard BTC locked on Bitcoin, rather than relying on wrapped tokens or federated bridges. To address the fact that SPOs cannot directly observe Bitcoin state, BIFROST uses Watchtowers—open participants who compete to submit confirmed Bitcoin blocks to Cardano. Anyone, including end users, can become a Watchtower. This permissionless design eliminates the trust assumptions present in most cross-chain bridges.

BIFROST prioritizes security and availability over speed or low cost.

More technical details: BIFROST Technical Documentation

§BLISK Framework: New Complex Boolean Logic Encoding for Optimized Bitcoin Authorization

A recent study introduced BLISK, a framework that compiles monotone Boolean authorization policies into a single signature verification key. BLISK ensures that only the subset of signers satisfying the policy can produce a standard, constant-size aggregated signature.

BLISK achieves this by using:

• n-of-n multisig to implement “AND” logic;
• Key agreement protocols to implement “OR” logic;
• Verifiable group operations (e.g., based on the 0-ART framework).

Additionally, BLISK avoids Distributed Key Generation (DKG), allowing users to reuse long-term keys; supports publicly verifiable policy compilation; and implements non-interactive key rotation.

By compiling monotone Boolean policies into a single verification key, BLISK enables fine-grained control over who can spend Bitcoin without compromising privacy or efficiency. It keeps policy complexity off-chain while leveraging cryptographic primitives such as MuSig2, Elliptic Curve Diffie-Hellman (ECDH), and non-interactive zero-knowledge proofs, ensuring privacy and security without reducing the expressiveness of transactions.

§Reducing PoW Dependence on Mempool and Consensus Time via Compressed Blocks and Delayed Verification

The author points out that although current proof-of-work (PoW) blockchain protocols show significant potential, they still face inherent limitations in scalability, efficiency, and decentralization. While compact block propagation reduces bandwidth and propagation delay under ideal network conditions, performance suffers in practice due to mempool inconsistencies among nodes.

This paper proposes a new block propagation and consensus protocol designed to reduce reliance on mempool synchronization. By redefining the PoW process, nodes can start mining immediately on compressed transaction IDs within a block, even before fully verifying transactions. Full transaction validation occurs in parallel via delayed verification.

Results show that this approach can process more transactions faster while maintaining Bitcoin’s decentralization and security. For example, with 10MB blocks, it achieves approximately 66.7 TPS.

§OptiBridge: Trustless, Low-Cost Bridge Between Lightning Network and Ethereum

The authors note that conventional bridge designs assume that events on the source ledger are publicly observable. However, in layer 2 payment channels like Lightning, channel state updates occur off-chain and are private between counterparties.

To address this, they propose OptiBridge, a bridge connecting a payment channel (e.g., Lightning Network) to a smart contract blockchain (e.g., Ethereum). It guarantees safety and liveness without introducing additional trust assumptions and is fully compatible with existing Lightning and Ethereum technology stacks.

Under normal conditions, OptiBridge uses an optimistic execution path: if both channel parties are honest, they reveal a pre-agreed secret to materialize the intended state on the target chain. To handle faults and adversarial behavior, OptiBridge provides a dispute path via a contract deployed only when necessary.

In the optimistic path, deployment and proof costs are significantly reduced. In dispute scenarios, contract deployment costs 2,785,514 gas, with core dispute calls costing even less. Analyses show rational users will strictly prefer the optimistic path, while the dispute mechanism prevents fund theft and imposes higher penalties and delays for protocol deviations.