TLDR

1. We want to make proofs on mobile
2. Mopro is a toolkit for ZK app dev on mobile
3. Let's make ZKPs on mobile great together

PART 1

We want to make proofs on mobile

Why client-side proving?

Let's put the "Zero Knowledge" back in ZK.

Zupass: Crypto-native identity

Aadhaar: Real-world identity

More examples…

Client-side proving

• Secure: User generates claims
• Fast: Good performance for big circuits
• Friendly: Easy to use and robust

Browser vs native

• Security: OS-level security
• Performance: Native performance
• Affordances: Better integration with phone
• Trade-off: Complex to develop and distribute

PART 2

mopro is a toolkit for ZK app dev on mobile

What is mopro?

• Toolkit: set of libraries and utils
• Goals
  • Modularity
  • Developer-friendly
  • Performance
  • Multi-platform
• Foundry for ZK app dev

mopro-cli 1-2-3

# Create a Circom project with iOS and Android support
mopro init --platforms ios, android

# Prepare circuit and artifacts
mopro prepare

# Build for iOS
mopro build --platforms ios

# Also options for testing, exporting bindings, etc

Example project

> tree -L 1
.
├── README.md
├── android              # Android project
├── core                 # Circom circuits, Rust wrapper
├── ios                  # iOS project
├── mopro-config.toml    # Project config
├── ptau
└── target

mopro-config.toml

[build]
ios_device_type = "device" # x86_64, simulator, device
android_device_type = "arm64" # x86_64, x86, arm, arm64
build_mode = "release" # debug, release (recommended)

[circuit]
dir = "core/circuits/keccak256"
name = "keccak256_256_test"
ptau = "19"

[dylib]
use_dylib = true   # true, false
name = "keccak256" # Name of the dylib file

Example app (XCode)

Architecture

Architecture

Circom

Most widely used DSL for client-side proving

mopro-core

• Core Rust library with multiple adapters
  • Starting with Circom, easy to add more
  • API for init/prove/verify, serialization etc
• Circom: Use circom-compat to load circuit
  • Witness gen native or via wasmer
  • Proving done natively with ark-groth16

mopro-ffi

• FFI: Talking across language barriers
• Bridge between Rust and Swift/Kotlin/Python
• Wraps Rust API, deals with lowering/lifting
• UniFFI to generate bindings for languages
• Support iOS, Android, and React Native

UniFFI

App (Anon-Aadhaar)

User

Just wants things to work

Zooming back out

Making life of app developer easy

DevEx: mopro-cli 1-2-3

# Create a Circom project with iOS and Android support
mopro init --platforms ios, android

# Prepare circuit and artifacts
mopro prepare

# Build for iOS
mopro build --platforms ios

# Also options for testing, exporting bindings, etc

Modularity

• Platforms: Adding support for e.g. Python trivial
• Proof systems: Adding new proof systems easy
• Tooling: Two birds with one stone
  • FFI, serialization, linking, packaging etc
  • Rust core: Schelling point for ZKP
• Public good: Not tied to specific business
  • Thanks PSE and 0xPARC for grant!

Where are we now?

• Anon-Aadhaar v1 showcase app
  • AA: Constraints up x10 from 160k to 1.6m
  • Also Proof-Of-Passport
• Performance
  • Understand limits of client-side proving
  • Native witness generation, arkzkey loading
• Improve DevEx
  • mopro-cli 1-2-3
  • API, React Native support, distribution

Client-side proving: How big can circuits be?

PART 3

Let's make ZK on mobile great together

You are nobody

Contribute

• Try it out and provide feedback
  • Write ZK apps in it, easy with mopro-cli
  • Monday workshop
• Community project
  • More platforms
  • More proof systems
  • Performance improvements
  • Docs, API, …
• ZK grants available

Contribute (cont)

• Platforms: React Native, Web?
• Proof systems: Halo2, Noir, …
• Performance: Native witness gen, GPU…

Contributors etc

• Downstream, upstream and main
• 0xPARC/PSE, Vivian, Yanis, Moven/Foodchain, Phil/Remco, Aaryamann/Vac, Florent, …
• You?

Recap

1. We want to make proofs on mobile
2. Mopro is a toolkit for ZK app dev on mobile
3. Let's make ZKPs on mobile great together

The future is ZK.

The future is mobile.

The future is now.

Thank you

• Questions?
• Mopro
  • Repo: github.com/oskarth/mopro
  • TG: t.me/zkmopro
• Oskar
  • X/FC: @oskarth
  • Site: oskarth.com

Performance notes

• Keccak256 (150k constraints): 1.5s
  • ~x10 faster vs comparable circuit in browser
• Anon-Aadhar 1.6m
  • 10s witness gen (wasm), 20s prover time
  • arkzkey load slow (~1.5m)
  • arkzkey size ~500mb (50% smaller)
• Bottlenecks: memory, loading zkey, and wasm witness generation