Opening Ceremony

State of Lightning Privacy

An overview of the current state of Lightning privacy, and recent developments.

Mapping the Space of Network Privacy Solutions: Features and Limitations of Lightning, Dandelion, VPNs, and Mixnets

Internet routing protocols were not designed for privacy. As a result, network communication metadata is exposed by default and available for collection by any network intermediary or eavesdropper. A number of solutions have been proposed to mitigate network privacy threats, typically involving routing traffic through various intermediaries rather than sending it directly. This includes the Lightning Network, Dandelion, VPNs and mixnets. This talk will review these solutions and discuss their privacy features as well as their limitations with respect to different network adversary models.

ASmap Workshop

ASmap is a Core feature that helps prevent eclipse-style attacks on your node by building a map of IP networks to the AS that owns them. In this workshop we'll get familiar with the problem and the tools to help address it by generating an ASmap.

Payjoin: Scaling is Privacy

Privacy and Scaling are often viewed as competing goals, but they go hand in hand. The Lightning Network is arguably the most widely used privacy tool on Bitcoin, despite not being its explicit purpose. This talk re-frames Payjoin in this context.

State of Bitcoin Privacy

What’s missing, what's on the roadmap, and what’s still to build.

Coinjoin, Joinpool and Octojoin

- Coinjoin using joinstr protocol - Joinpool (w/ covenants) - Octojoin (an alternative for payjoin with less interaction and better privacy)

UTXOracle: Historical Significance of the On-Chain Price

Before UTXOracle, all bitcoin price feeds relied on external exchanges, introducing trusted third parties and blind spots into what should be a trustless system. UTXOracle takes a different approach: it derives price directly from the bitcoin blockchain by identifying statistically significant transaction flows, without relying on off-chain data. This talk introduces UTXOracle as a novel lens for understanding Bitcoin’s internal price signal, a signal that emerges from crowdsourced economic activity rather than being imposed by markets. We’ll explore how UTXOracle reads directly from one's own node, defines canonical prices through a simple cluster-centering algorithm, and how its method reveals patterns lost in exchange-centric views. Beyond just a tool, UTXOracle invites us to consider what it means for Bitcoin to price itself. We'll discuss why this matters for censorship resistance, timestamped economic history, and future applications like sovereign node pricing and decentralized oracle infrastructure.

Hackathon Kickoff

Who’s the fastest privacy hacker in Riga? We’ll take the top 5 teams from the Expo and give them the opportunity to impress the judges live.

Hackathon Team Building

Optional!! Come find a team to work with. We’ll help everyone find someone else to work with, and then you can start making plans for what you’ll build over lunch.

Hackathon Ideas Workshop

Optional!! Need a good idea to hack on? Come ideate with the btc++ staff and hackathon veterans.

Hacking Time

You don’t have much time to work at this bitcoin++, make the most of it

Hackathon Expo

Showcase of all the hackathon projects. Round robin judging will happen during this period.

Comparing Coinjoin Implementations

How do the current widely used coinjoin protocols compare, and how private are they actually? We'll go through the big three: payjoin, joinmarket, and wasabi, and review what they are and what flaws they have.

The state of ecash design: progress, risks, and what’s ahead.

Over the past few years, Cashu has gone from an experimental concept to a growing ecosystem. I want to highlight the major development breakthroughs that helped get us here, the problems we’re still solving, and what might be coming next. I’ll go over stuff like: How people are finding mints (and how tools like

Privacy Lego: Where Does Cashu Fit in Your Bitcoin Stack?

Bitcoin gives us sound money, Lightning brings instant payments, but where does Cashu fit? This interactive session explores Cashu's unique role in the Bitcoin ecosystem. Through hands-on examples and live demonstrations using Rust Cashu implementations, participants will discover when and why to integrate Cashu into their Bitcoin applications.

Optimizing coinjoin transactions

As Bitcoin's largest coinjoin coordinator, my goal is to optimize rounds for stability while consuming block space efficiently. There is a tradeoff between speed, cost, and reliability when configuring round parameters. Additionally, I seek to refute some commonly spread myths about coinjoins while also addressing their limitations.

Be your own ISP - non KYC internet access

How much of an identity do you really need in order to communicate? TollGate is a WiFi captive portal that accepts e-cash for internet access. You can buy internet access from my TollGate and resell it to someone outside of my to form a "mesh network" that doesn't require a routing algorithm. Your business decisions determine the route of the traffic. Let's try it out in the hands on workshop!

Build your own BTClock

If you buy a workshop kit for EUR 150,- payable in Bitcoin (on-chain or LN), you can build your own FOSS/H BTClock during a guided building session. Depending on the available time, I could explain about how the project started and give a high overview of the hardware (15 minutes). The building itself is about 30 minutes as we created kits that only require screwing it together (no soldering required).

Adversarial Interactive Transaction Construction

niftynei wrote the interactive transaction protocol for Lightning. In this talk, she walks through open problems with building collaborative transactions in a decentralized network

El Tor - A high bandwidth Tor network fork incentivized with Bitcoin

Come learn about the architecture of the El Tor network! El Tor is a high-bandwidth Tor network fork, incentivized by the Bitcoin Lightning Network. Users can host El Tor relays and earn sats for sharing their bandwidth. The urgency for such a network has never been greater, especially in light of escalating privacy threats globally—from Brazil's VPN prohibition to the legal challenges faced by Telegram's Pavel Durov. El Tor aims to transcend the existing boundaries of the Tor network and to scale beyond its current limitation. The project was inspired by the cypherpunk vision for a private internet. BOLT 12 offers (with blinded paths) was the catalyst to build such a network. Lightning is used for privately paying relays out of band. A higher bandwidth and more reliable Tor network can lead to future services being launched as hidden services by default, instead of "clearnet" (or KYC'd) servers. - Read the spec here

Miniscript

Bitcoin Miniscript: The Key to Smarter Wallets

payjoin ux challenges

Challenges with Payjoin user experiences

Hackathon Finals

Top finalists who make it out of the Expo will be invited to present their projects to compete for the top prize.

What you don't want to hear

72% of the world currently lives under authoritarian rule. This year is the 18th consecutive year of decline in the number of democracies worldwide. We have come to expect limitations on free speech and free association from places like China, India, and large parts of Africa; but not Europe, the UK, and the US are becoming increasingly draconian in their limitations on speech, association, and protest. More than ever before we need permissionless, unstoppable tools that give us control and agency over who we talk to and what we can say. We can no longer trust centralized tech and the stakes are high. Nostr offers us a real chance at building these tools. It's unique characteristics combined with strong modern encryption techniques give us the ability to have all truly private conversations, while completely hiding metadata, all while using public relay infrastructure. Make no mistake, this is a race. Either those in control will continue to tighten their grip on our liberty or we will build tools that are outside of human interference and control.

Operation ORCHESTRA 2.0 Annual Status Report

A decade ago, Operation ORCHESTRA unveiled the blueprint for covert success in the technological domain—and it surpassed all expectations. Following its resounding achievements, an extension was swiftly approved to lay the groundwork for ORCHESTRA 2.0. This year's briefing will update decision-makers and program liaisons on the goals, breakthroughs, and strategies employed in the highly classified next chapter of systemic orchestration in the decentralized era.

Private Web Payments with Cashu (and nostr)

In this workshop we will explore how we can utilise open networks like Cashu and nostr to create privacy preserving payment rails on the web.

Cashu: Bitcoin micropayments with maximum privacy

To come…

CISA

- Pros and Cons of a CISA softfork (what's in the HRF Report) - Current state of proposal and implementation

Monetary Hidden Services

Run software that provides paid privacy-focused services and hides your lightning payment info in a manner similar to tor

Light Clients Aren't Dead!

The current state of bitcoin clients outside of Bitcoin Core typically trade off speed for privacy. 2140 is attempting to bridge the gap to bring better privacy for resource-constrained applications. The talk will cover the current state of BIP 157/158 compact block filters, strategies for implementations to incorporate compact block filters to provide better privacy for their users, and ideas for future silent payments wallets built with private light clients.

Privacy issues in the Bitcredit network

Bitcredit main goal is to make the use of Bitcoin in the real economy possible. "Orange-pilled businesses". The protocol is based on the concept of peer to peer credit contract between companies based on a proven financial instrument such as a bill of exchange denominated in bitcoin. And further adding liquidity to bills of exchange based on ecash, with which companies will be able to pay their workers. In this talk I would like to focus on anon mode, a mode in the application that will allow businesses to remain completely anonymous.

Privacy beyond Bitcoin

Why you should work on privacy projects that aren’t “bitcoin”. An overview of technologies and contribution opportunities that are key to building the cryptoanarchist project. * Network level privacy (e.g. Mixnets) * Paths to KYC-resistant hosting * Autonomous, self-replicating applications * Private, decentralized communities

Timelocks and Their Use in Recovery Solutions

Absolute and Relative Timelocks in Bitcoin are necessary for 2nd layer solutions, but what else can we do with them? Let's dive into how timelocks operate in Bitcoin, what they can\cannot do, and how we can use them to recover our Bitcoin in case our seed was lost.

Lessons from Building Vexl: Balancing Encryption, Anonymity, and UX in Bitcoin Apps

What does it take to build a peer-to-peer Bitcoin app that truly respects user privacy—without sacrificing usability? In this talk, we’ll share lessons learned from developing Vexl, a no-KYC, client-first Bitcoin trading app. We’ll explore the technical and architectural challenges of storing encrypted data in the database, designing anonymous communication and trust models, and crafting a user experience that remains intuitive despite strict privacy constraints. If you’re building in the Bitcoin space and care about user privacy while creating apps people can actually use, this talk is for you.

Closing Ceremony