# Building ZK Apps That Run on Your Phone I Moven Tsai

- Speakers: [Moven Tsai](https://streameth.org/speakers/moven-tsai)
- Channel: [ETHGlobal](https://streameth.org/ethglobal)
- Date: 2025-11-09
- Duration: 18:32
- Topics: Morro, mobile ZK, iOS, Android, Flutter, React Native, Rust FFI, uniffi, Circom, Halo2, Noir, RISC Zero, WalletConnect, onchain verification, Semaphore, JWT proofs, Aadhaar, geolocation proof, Secure Enclave, TEE, MPC, NFC, tap to prove, zkPDF, identity registry, revocation, mobile bindings, CLI workflow, ECDSA proof on device
- Watch: https://streameth.org/watch/yt-wmCZ7cpDi68
- YouTube: https://www.youtube.com/watch?v=wmCZ7cpDi68

## Description

Moven Tsai (Ethereum Foundation) walks through Morro, a toolkit for building mobile ZK apps that run directly on iOS and Android (including Flutter and React Native). Morro wraps Rust code, exports mobile bindings, and integrates with popular proving stacks—Circom, Halo2, Noir, and RISC Zero—so developers can compile circuits once, generate bindings, and execute proofs and verification on phones. The CLI flow is simple: morro init to scaffold a Rust workspace, morro build to generate iOS or Kotlin bindings for the chosen architectures, and morro create to scaffold mobile app templates. For non-Rust developers, Morro also ships native SDKs (Swift, Kotlin, Dart) and cross-platform templates, plus WalletConnect-enabled verifier demos for onchain flows.

Tsai showcases ready-to-fork templates and real app ideas: proof of geolocation, Semaphore-based membership proofs, Aadhaar integrations, JWT domain proofs, and a RISC Zero template that proves ECDSA on device (noting mobile proofs are slower, roughly 90–120 seconds). He highlights patterns for exporting arbitrary Rust functions to mobile via uniffi macros, hot-rebuilding circuits and bindings, and updating app integrations with morro update. The talk closes with hackathon tracks and ideas, including credential sharing from signed PDFs (with zkPDF), unified ZK identity registries with revocation, NFC tap-to-proof UX, mobile-native sensors like GPS and camera, and ZK TEE or MPC-based TEE-on-mobile explorations.

00:00 – Why ZK on mobile matters
01:07 – What Morro is: Rust wrapper, ZK integrations, mobile bindings
01:27 – Supported stacks: Circom, Halo2, Noir, RISC Zero
02:13 – Platform support: iOS, Android, Flutter, React Native
02:37 – Morro CLI overview and recent refactor
03:53 – Install options: main branch vs legacy stable
05:03 – Core workflow: init, build, create templates
05:29 – Building bindings per architecture and simulator vs device
05:51 – Scaffolding iOS, Android, Flutter, React Native apps
06:16 – Circom integration: artifacts, setup, verify on device
06:51 – Exporting arbitrary Rust logic with uniffi
07:52 – Rebuilding circuits and hot updating bindings
08:21 – Use cases and templates tour
08:55 – JWT domain proofs on mobile
09:17 – Semaphore membership: private check-ins (Zuma)
10:03 – Aadhaar integrations and QR scanning, photos
10:30 – Geolocation proofs and GPS ideas
10:53 – Onchain verification templates with WalletConnect
11:27 – RISC Zero on phone: feasibility and timings
12:25 – Example projects: face match in Secure Enclave, ECDSA proofs
13:47 – Wearables and access control demos
14:14 – Additional zk stacks and open-source references
14:37 – Hackathon prize tracks with zkPDF
14:58 – App ideas: credentials, games, matching, NFC tap-to-proof
15:53 – Infra ideas: unified ZK registry and revocation
16:27 – NFC and native sensor exploration
17:00 – ZK TEE or MPC notarization on mobile
17:58 – Resources: slides, GitHub, Telegram, help

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🇮🇳 *ETHGlobal New Delhi*
This workshop is specifically for ETHGlobal New Delhi, a 3-day hackathon held September 19-21 at the India International Convention & Expo Centre, bringing together the most skilled web3 developers, designers and product builders from all around the globe for a weekend-long adventure to advance the Ethereum ecosystem! Watch the full ETHGlobal New Delhi 2025 playlist here: https://www.youtube.com/playlist?list=PLXzKMXK2aHh7zCFW3hBqatZ18rQaYeEJL
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