0016 WASM-based Rust Libraries in Client

Author:: Assistant
Created:: 2025-10-29
Status:: Accepted
Tags:: compression flutter_rust_bridge key-derivation rust wasm

Context¶

Key derivation and compression should be implemented once and reused across platforms. Relying on a single Rust codebase compiled to WASM reduces duplication and drift.

Assumptions¶

Flutter can interop with Rust via flutter_rust_bridge and WASM for Web.
Performance is sufficient for client side operations.

Decision¶

Adopt WASM based Rust libraries for key derivation and compression exposed to Flutter via flutter_rust_bridge. Ship platform appropriate artifacts and loaders, including web worker initialization for WASM.

Rationale¶

Single implementation ensures consistent behavior and security properties. Rust offers strong safety guarantees and good performance for cryptographic workloads.

Implementation Guidelines¶

Provide JS loaders that initialize WASM with correct MIME types and worker setup.
Validate outputs with shared test vectors across platforms.
Version and package artifacts for reproducible builds.

Risks¶

WASM hosting requirements can be tricky on some environments. Bridge layers add build complexity and require CI coverage.

Consequences¶

Consistent cryptographic and compression behavior across Web and Mobile. Slightly more complex build and packaging steps.

More Information¶

flutter_rust_bridge