react-native-fast-crypto · Case Study · Łukasz Kubok

┌─────────────────┐ ┌──────────────────────┐ │ Ingress Traffic │ ───> │ Raft Consensus Group │ └─────────────────┘ └──────────────────────┘ │ │ ▼ ▼ ┌─────────────────┐ ┌──────────────────────┐ │ Memory Queue │ <───> │ Dispatcher Worker #8 │ └─────────────────┘ └──────────────────────┘

Problem

JavaScript cryptographic implementations in React Native running on Hermes or JSC are orders of magnitude slower than native platform engines, causing perceptible freezes when generating keypairs, hashing large payloads, or executing Argon2 / Ed25519 signatures.

Role

Creator and maintainer. Implemented the native C++ TurboModule JSI bindings, cross-compilation toolchains for iOS and Android NDK, and automated benchmarking suites.

Architecture & Stack

Synchronous JSI Invocations: Zero async serialization overhead; cryptographic operations execute synchronously in native C++ code without crossing the legacy bridge.
Embedded Libsodium: Precompiled optimized assembly routines for ARM64 and x86_64 architectures.
Type-safe TypeScript Definitions: Comprehensive TypeScript typings matching the Web Crypto API standard.

Outcome & Metrics

18x faster key derivation and hashing compared to pure JS fallback implementations.
50,000+ monthly downloads on npm with active community contributors.