README.md

Secure Element Library for Android and iOS

secure-env is a library that allows for key generation and signature creation using the mobile secure element.

Supported targets

• aarch64-apple-ios
• aarch64-apple-ios-sim
• x86_64-apple-ios
• aarch64-linux-android
• armv7-linux-androideabi
• i686-linux-android
• x86_64-linux-android

iOS

iOS bindings are done via security-framework. This is a safe wrapper around Apple's security.framework.

Android

Android bindings are done via jni-rs. It was discussed to use do this via IPC (Binder) or HIDL, but jni was chosen for its similicity and available documentation.

Beneath these bindings it fully relies on KeyStore. During key generation, based on the support version, setIsStrongBoxBacked is set to make sure the key is store in hardware. If this is not supported we fall back to a lower level of security setUserPresenceRequired.

NOTE: there still needs to be some additional research done into the exact garantuees that setUserPresenceRequired provides. If it means TEE, it is all good.

Additional setup

Due to time constraints, currently some additional setup is required for Android to fully work. This has to do with accessing the JVM pointer from Rust. If something like android_activity is used, take a look at the android example. If this library is used from a React Native context, or native Android app, include the following in your project:

package id.animo;

public class SecureEnvironment {
    static {
        System.loadLibrary("secure_env");
    }


    public static native void set_env();
}

Afterwards, you can call SecureEnvironment.set_env before making any calls to the library. Afterwards everything should be set up properly.

Features

	ios	android
generate keypair	✅	✅
get keypair by id	✅	✅
get public key	✅	✅
sign	✅	✅

Usage

Add the dependency

cargo add secure-env

// src/main.rs
use secure_env::{SecureEnvironment, SecureEnvironmentOps, Key, KeyOps};

fn main() {
    let key = SecureEnvironment::generate_keypair("my-key-id").unwrap();
    let key_from_id = SecureEnvironment::get_keypair_by_id("my-key-id").unwrap();

    let msg = b"Hello World!";

    let public_key = key.get_public_key().unwrap();
    let signature = key.sign(msg).unwrap();

    assert!(public_key.len(), 33);
    assert!(signature.len(), 64);
}