VRF-WASM

A pure-Rust VRF (Verifiable Random Function) implementation optimized for WASM environments, including web browsers and smart contracts.

Project Structure

This repository contains multiple crates for different use cases:

vrf-wasm/ - VRF for WASM environments (e.g browser workers)

Complete VRF implementation with key generation, signing, and verification:

• Key Generation: Secure VRF keypair creation
• Proof Generation: Create VRF proofs with randomness
• Verification: Verify VRF proofs and outputs
• WASM Compatible: Works in browsers and Node.js
• Size: 175KB optimized

Use for: Client-side applications, oracles, services that need full VRF functionality

vrf-wasm-js/ - JavaScript Bindings

Browser and Node.js bindings for the full VRF library:

vrf-contract-verifier/ - NEAR Contract VRF Proof Verifier

Minimal verification-only library optimized for smart contracts:

Use for: Smart contracts that only need to verify VRF proofs

Feature Comparison

Feature	vrf-wasm	vrf-wasm-js	vrf-contract-verifier
Key Generation	✅	✅	❌
Proof Creation	✅	✅	❌
Proof Verification	✅	✅	✅
Browser Support	✅	✅	❌
Node.js Support	✅	✅	❌
NEAR Contracts	⚠️	❌	✅
Generic WASM	⚠️	❌	✅
Dependencies	Many	Many	Minimal

⚠️ = not optimized

Binary Size Comparison

Compiled WASM binary sizes (optimized release builds with opt-level="s") as follows:

Library	Binary Size	Size Ratio	Use Case
vrf-contract-verifier	86 bytes	1x (baseline)	Proof verification only
vrf-wasm	175 KB	2,090x larger	Full VRF operations
vrf-wasm-js	267 KB	3,183x larger	Browser-optimized

The size difference between vrf-contract-verifier and vrf-wasm comes from:

1. Scope:

   • vrf-contract-verifier: Only verification logic
   • vrf-wasm: Complete VRF implementation (keygen, signing, verification)

2. Dependencies:

   • vrf-contract-verifier: Minimal crypto primitives only
   • vrf-wasm: RNG, serialization, encoding, multiple hash functions

3. Target Environment:

   • vrf-contract-verifier: Optimized for smart contracts
   • vrf-wasm: General-purpose WASM environments

Debug vs Release Optimization

Library	Debug Size	Optimized Release	Optimization Factor
vrf-wasm	8.4 MB	175 KB	49x reduction
vrf-wasm-js	10.1 MB	267 KB	39x reduction
vrf-contract-verifier	N/A	86 bytes	Ultra-minimal

Smart Contract Platforms

Supported Platforms (vrf-contract-verify)

• ✅ NEAR Protocol: Native integration with near-sdk
• ✅ Generic WASM: Any WASM-based contract platform such as Sui but this needs testing.

WASM Compatibility

Both vrf-wasm and vrf-contract-verifier crates are designed for WASM environments:

• No std: Compatible with no-std environments
• No global statics: Avoids initialization issues
• Pure Rust: No external dependencies on system libraries
• Optimized builds: Minimal code size with --release builds

VRF Specification

Implements ECVRF with:

• Curve: Ristretto255 (prime-order group over Curve25519)
• Hash Function: SHA-512
• Suite String: sui_vrf
• Output Length: 64 bytes
• Challenge Length: 16 bytes

License

Apache-2.0 - See LICENSE for details.