Crypto SDK usage in React Native

[flyingleafe]

Hello. We are developing an application with end-to-end encrypted chat functionality in React Native, and intend to use Matrix codebase for that purpose.

We initially planned to simply use matrix-js-sdk, doing basically the same which was started in matrix-rn-sdk, but never quite finished. We reused the CryptoStore implementation from this repository, but as it turned out, Rust Crypto API exposed by matrix-js-sdk never uses the provided CryptoStore implementation for anything except from old data migration to the new storage. The new (actual) storage could only be backed by IndexedDB (https://github.com/matrix-org/matrix-rust-sdk-crypto-wasm), which is unavailable in React Native environment

Currently, I see two possible paths forward for us:

• Use matrix-sdk-crypto bindings for Android and iOS as native modules in React Native, and redefine the crypto module in matrix-js-sdk in some sort of way which will be reusing those native modules in the same manner the matrix-sdk-crypto WASM module is used;

• Inside matrix-rust-sdk-crypto-wasm, make the crypto storage implementation based on some abstract key-value storage trait, and let JS code provide the storage implementation specific to the platform, and run all that through react-native-webassembly.

I am ready to partake in either endeavour and share the results with the comminity. However, I am not sure what will be easier and what will be more in line with the general direction of Matrix codebase development.

Any help regarding that would be much appreciated.

[zzorba]

@flyingleafe today is your lucky day.

There is a newer open-sourced set of bindings for RN built using uniffi directly that you can find here: https://github.com/unomed-dev/react-native-matrix-sdk. It is built using the https://github.com/jhugman/uniffi-bindgen-react-native project which allows for direct usage of any uniffi enabled rust library in react-native.

It currently supports all features of the matrix-sdk-ffi crate for iOS and Android. The maintainers of both libraries hang out in this chat room https://matrix.to/#/#uniffi-bindgen-js:matrix.org, if you run into any issues.

[flyingleafe]

@zzorba wow, that seemingly simplifies things a lot! Thank you very much for this info, Google was much less helpful in discovering those recent projects.

[bnjbvr]

Closing, as it seems the uniffi react-native bindings are sufficient to address this; feel free to reopen if you think it's not the case.