From June 20th to the 22nd, we hosted our 5th in-person ZK-focused hackathon in blazing Berlin, Germany, concluding the Berlin Blockchain Week! It had been a long time coming and we all were excited to host this again after waiting 10 long months since the 4th edition in Montreal!
On Friday, the w3.hub team was amazing and opened the doors to their big venue in Kreuzberg to the ZK Hack community for this last weekend of the BBW, and for the 30th (!) event there in 14 days! (They’ve since dubbed this week the Berlin Blockchain Madness 2025..) ZK Hack took over and soon our neon colors, swag, and crowd kicked off ZK Hack Berlin!
As the weekend progressed, so did the temperature in Berlin, reaching a peak of 34 degrees on Sunday. An ice cream freezer was brought in, and we all welcomed the popsicles!
We closed off the hackathon with a great ceremony, and official goodbyes, but as the dusk fell many made their way to the nearby biergarten to enjoy the more soothing summer evenings of Berlin.
Day 1: Setting the Stage
Friday at 5.30 pm, with people pumped after 2 weeks of events, the hackathon started off with a bang as soon as we opened the doors of the w3.hub building in Kreuzberg! Long-time ZK Hack friends and new faces came in, some attending their nth event of the week, others just joining for the weekend to soak up the vibe and connect with our community.
Kickoff
Time had come for the official ZK Hack Berlin Kickoff, where the ZK Hack team outlined the weekend’s schedule and all important information (prizes! 👀), and where sponsors took the stage to introduce their bounties and what they were hoping to see built or implemented by the hackers.
Happy Hour
Right after dinner was the perfect time for a Friday night Happy Hour, with the help of our partner Xion! In good Berlin fashion we opened the bar with a choice of softs, beers, white wine in ½ bottles, Jager and special treats!
We were joined by many ZK friends that evening, and it was the perfect moment for sharing hack ideas & forming teams for the rest of the weekend. Many hackers jumped straight in however and started hacking until we closed!
Day 2: 200% Hacking
All of Saturday (and well into Sunday morning!) was time for hacking, with Office Hours throughout the day for participants to meet the engineering teams from our Based Sponsors Irreducible and Aleo.
As the day progressed, we had the chance to interact with the hackers, noting the impressive quality and variety of projects shaping up for Sunday submissions. Here are some notable projects that would later contend for the top prizes. Beware, this is not a very short list, there were truly a lot of projects that our jury had to debate over (and most were awarded bounties, too):
- zkEMV: MrNerdHair built an identity provider on the Hyli blockchain that lets you use your payment card (Europay, Mastercard, Visa) as a hardware wallet,
- MPSee: Kai Jun, Bing & Purple built a scheme that allows a user to distribute secret shares to a group of guardians, who can collectively help recover a wallet without ever learning the user’s actual address or messages they are signing,
- Zk-fabric-rs: Arpit worked on a Polylithic Syntax ZK Joint Proof System,
- TreeFold: Simon & Daniel implemented tree-style folding in the HyperNova folding scheme,
- Privatestargatefinance.eth: Ben rebuilt stargate.finance with a privacy layer on top,
- bargo: Franco built an opinionated, developer-friendly CLI for Noir development,
- Leaf Me Hard: ordian, Syed & Andrew attempted to solve a problem of Merkle (Patricia) Trie (MPT) inclusion compression,
- zkML-GOODBLEEP: CJ built a swarm of agents that competes to generate the BEST music,
- ZK Shroud Arena: Nuttakit & Lattawit built a real-time proof-of-location game with custom zones,
- Kinky Swap: Gianfranco & Reymo built a tool for non-vanilla cross-chain swaps enabling atomic, anonymous cross-chain bridges and swaps between Aleo and Aztec,
- Konnektoren: Christian & Sofiia built a tool where users need to privately verify their identity to obtain a certificate on a learning platform,
- ZKAZ: Morris built a P2P crypto betting platform that leverages ZKPs for fair and transparent bet resolution.
Hacking continued well into the night …
Day 3: Last Push
There’s no second best to the vibes in the last few hours before submission of a hackathon! Last touches to the projects, video presentation recordings, high tension (… or chill, for some!). The deadline was noon!
Jury
For this edition, hackers had the chance to present to an amazing group of 20(!) judges that were with us throughout the weekend:
Anna Rose (ZeroKnowledge.fm), Aurelien Nicolas (Inversed.tech), Billy Rennekamp (Trifle), Connor (Celestia), Dev (osmosis), Evi / Tranquil Flow, Gaylord (Miden), Hudson Jameson (Polygon Labs), Koen van Marrewijk (ZKV), Liam Eagen (Alpen Labs), Lisa Akselrod (Aztec), Marko (Binary Builders), Praneeth Srikanti (Ethereal Ventures), Rene Reinsberg (Celo / Self), Stefan (Gnosis), Susannah Evans (IBC), Sylve Chevet (Hyli), Theo Madzou (ZKPassport), Yulia (Anoma) and Zeng Huy Tay (Gnosis).
45 projects were submitted on Sunday, and we broke the judges into 5 teams of 4, calling hackers to present to our judges. It was really challenging to dive in in such a short time, especially for some very technical projects. But they made it through, and after 1.5 hours, all the projects had been reviewed and the group had their shortlist.
The judges got back together and a small group broke out to review the most technical projects and choose the chewing glass winner. The remaining judges shared their experience in the judging rooms and started to narrow down the top teams and eventually were able to name our 1st, 2nd, and 3rd place winners. The remaining shortlist candidates were shared with the larger hacker group, so that the community could choose the hackers choice!
In parallel, we had the sponsors judging their respective bounty tracks, engaging with the various projects who were eligible to their own criteria.
We can’t express how grateful we are that this amazing group of judges spent their Sunday with all of us – Thanks again for your invaluable insights in judging such a great set of projects!
Closing Ceremony
By 16:00, everyone was ready for the closing ceremony! We had the Based Sponsors join us on stage to give out their bounty prizes. Congratulations to Roman (Zerocheck Optimization), Sean & Igor (The Last Checksum) for taking home Irreducible’s bounties, and to Mohit (LeoMafia), Gianfranco & Reymo (Kinky Swap), and Jordan (Pessimistic ZK Fair Liquidations) for claiming Aleo’s bounties!
It was then time for the Winners of ZK Hack Berlin! We announced our Chewing Glass, Hackers’ Choice and Top 3 winners of ZK Hack Montréal. Over 40K$ in prizes were awarded to the hackers that day!
The winners had the opportunity to present their work to the audience, showcasing the details of their projects and the impressive results of their efforts.
ZK Hack Berlin Winners
And here are the winners…
✨ Hacker’s Choice ✨
The Hacker’s Choice Prize went to TruthSeeker: Romario built a privacy-first proof-of-video authenticity platform that embeds cryptographic proof directly inside video files using steganography.
repo: https://github.com/RomarioKavin1/TruthSeeker
✨ Chewing Glass ✨
The Chewing Glass Prize, a ZK Hack favorite, went to Anon Proxies: Ying Tong, Nico, Andrija & Marcin built an implementation of the new crypto primitive: Anonymous, Timed and Revocable Proxy Signatures (https://eprint.iacr.org/2023/833)!
repo: https://github.com/therealyingtong/schnorr-tokens
🥉 Third Place 🥉
The ZK Hack 3rd Prize went to God’s Hand: Gabriel built a solution addressing the lack of transparency, privacy, and accountability in disaster relief and donations!
repo: https://github.com/GabrielGodsHand
🥈 Second Place 🥈
The ZK Hack 2nd Prize went to ZK-AntiCheat: pop_eax built a first-of-a-kind privacy preserving anticheat engine!
repo: https://github.com/zk-AntiCheat/
🥇 ZK Hack Grand Winner 🥇
And the ZK Hack 1st Prize went to ZeroHour: Leo & Georg pushed the limit of client-side ZKP generation by creating proofs of steps walked on a PineTime, an open-source smartwatch w/ only has 64kb RAM!
repo1: https://github.com/leonardoalt/InfiniTime/tree/zkhack
repo2: https://github.com/leonardoalt/InfiniSim/tree/zkhack
Congratulations to the winners of this edition, and to all the participants!
Bye for now
So many good projects came out of this edition (see for yourself the long list in this post!), making this edition a great showcase of the large scope of ideas and potential applications of ZK and programmable cryptography!
And just like that, ZK Hack Berlin came to an end!
A big shoutout to our fantastic partners – Based Sponsors Irreducible and Aleo,
We’re also grateful to our Community Sponsors Boundless, Horizen, Aztec, ZKPassport, Hyli, Arbitrum, Gnosis, Self, & Xion, our Prize Sponsor ZKV, and our Media Partner ZeroKnowledge.fm,
Thanks again to our judges, who did an incredible job reviewing all the fantastic projects submitted by the participants,
Much love to the ZK Hack team Anna, Quentin & Agni and to our host Gaylord,
To the volunteers that joined us this weekend, we hope you had a blast!
To the team at w3.hub, for hosting us and your big help with everything,
To Henrik for the AV work all weekend,
To Zero-knowledge Audiovisual Club for hosting a recording station all day Saturday, we’re excited to hear the hacker stories soon!
Thanks to our Platform partner Devfolio for supporting the hackers all weekend,
Lastly, a big big thank you to all the hackers, we can’t wait to see you at the next one!
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