ZeroBot
ZK reCAPTCHA: Human Verification for Discord
Created on 20th June 2025
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ZeroBot
ZK reCAPTCHA: Human Verification for Discord
The problem ZeroBot solves
The Problem It Solves
Humans are still solving CAPTCHAs, but bots are already bypassing them. Discord is full of bots that slip through verification.
Traditional methods are clunky, invasive, or easy to spoof. There's no reliable, private way to prove you're human.
How ZeroBot Makes it Easier and Safer
ZeroBot lets you prove you're human, once, and reuse that proof privately across apps. It offers a frictionless experience like OAuth, but decentralized, bot-resistant, and privacy-preserving.
No more captchas, no more leaks, just real humans, verified cryptographically.
Key Features
- Signed Challenge: The user signs a challenge with their Ethereum wallet, proving ownership.
- Identity Reuse: If the user has registered an identity (via zkPassport or Self), ZeroBot retrieves and verifies it instantly and privately.
- One Wallet per Identity: The system checks whether an identity already exists, enforcing a strict 1:1 mapping before creating a new one.
- Private Storage on Aztec: Identities are stored privately using Aztec’s encrypted state model, ensuring no public disclosure or on-chain fingerprinting.
- Modular & Reusable: Once created, the identity can be reused across platforms, just like OAuth, but without trusting any centralized provider.
Challenges we ran into
At first we struggled to understand how to deploy our contract on testnet. Fortunately, the GitHub repo is well structured, and after diving deeper, we realized it wasn’t as difficult as it seemed. Big shoutout to aztec-starter that it helped us understand the testnet account creation flow and gave us a solid foundation to build on.
Fortunately, the GitHub repo is well structured, and after diving deeper, we realized it wasn’t as difficult as it seemed. Big shoutout to aztec-starter, it helped us understand the testnet account creation flow and gave us a solid foundation to build on. It was a great reminder that even when things feel stuck, the right resources can unlock the path forward.
Tracks Applied (5)
ZK Hack Berlin Winners
Grand Prize: Best Overall Aztec Testnet Project
Aztec
Most Innovative or Technically Proficient Aztec Integration
Aztec
Best ZK App with Product-Market Fit
Arbitrum
Private Identity Verification
ZKPassport
Technologies used
Cheer Project
Cheering for a project means supporting a project you like with as little as 0.0025 ETH. Right now, you can Cheer using ETH on Arbitrum, Optimism and Base.

