Posts by Collection


Bitcoin’s P2P Layer Improvements

Bitcoin relies on the peer-to-peer layer for nodes to exchange transactions and blocks. We work on protecting this layer from spies, amateur hackers, and larger threats. We are also putting effort into making it more efficient so that Bitcoin becomes more accessible even under rough conditions in any part of the world.


Various Bitcoin protocols (Lightning, swaps, vaults, …) are still in their early stages, but we already can see some of the big challenges. Those protocols currently assume the possession of a UTXO by their participants. This is a scaling bound for a future with hundreds of millions of Bitcoin users. Another challenge raises from their unique on-chain fingerprint, which makes their use less private. Considering that some of them are privacy-oriented, the fingerprinting issue may result in imperfect fungibility. Coinpool is a solution to both problems.

Lightning Security and Privacy Research

The Lightning Network is the most deployed Bitcoin scaling solution aiming to serve as the next platform for the open financial future. The ambitious design of the LN comes with new classes of security and privacy attacks. Researching and mitigating them early is important to boost Lightning’s long-term trustworthiness and success.

Stake Certificates

Permissionless systems (not only Bitcoin and Lightning!) often suffer from Sybil attacks, because it’s hard to distinguish malicious fake entities from real honest users. We describe a new class of solutions: privacy-preserving proving of Bitcoin ownership. We discuss how this idea could work to combat channel jamming in the LN.


CoinPool, exploring generic payment pools for Fun and Privacy


We think that a wide range of second-layer protocols (LN, vaults, inheritance, etc) will be used by average Bitcoin users. We are interested in finding and addressing the privacy issues coming from the unique fingerprints these protocols bring.

Mitigating Channel Jamming with Stake Certificates for HTLC Traffic


In this post, we explore a different approach to channel jamming mitigation. We’re suggesting using UTXO ownership proofs (a.k.a. Stake Certificates) to solve this problem. Previously, these proofs were only used in the Lightning Network at channel announcement time to prevent malicious actors from announcing channels they don’t control. One can think of it as a “fidelity bond” (as a scarce resource) as a requirement for sending HTLCs.

The joyful journey of building Bitcoin


It’s 11th May in NYC. Even if the end of the world did happen, the streets of Manhattan are at peace for reasons of the sacred local commodity, coffee, still being fairly available. Equipped with your own dose, you’re jumping on your keyboard to browse the busy streets of the Bitcoin hive. It’s Monday and you have a lot to get down to. There is this Core PR to rebase for the thousandth time. A weird bug showed up in your payment channels implementation making them purple and you still have to grasp this musky mailing post about curve point 1080 hard flips.

TxWithhold Smart Contracts


In this article, we attempt to design smart contracts encouraging miners to withhold a certain transaction, to better understand how practical such smart contracts are.