MUSAP Android Library

MUSAP (Multiple SSCDs with Unified Signature API) is an Android library designed to simplify the integration of multiple Secure Signature Creation Devices (SSCD) with a unified signature API. It provides a set of tools and utilities to streamline the implementation of secure signature creation mechanisms in Android applications.

Features

• Multiple SSCD Integration: MUSAP simplifies the integration of multiple Secure Signature Creation Devices into your Android application.
• Unified Signature API: Utilize a unified API for signature operations, abstracting the complexities of individual SSCD implementations.
• Secure Signature Creation: Implement secure and standardized methods for creating digital signatures within your application.
• Customizable: MUSAP is designed with flexibility in mind, allowing developers to customize and extend its functionality according to specific project requirements.

Project Structure

Reference implementation app

We have a reference implementation app available that serves as an example on how to use the library. You can find the app project here.

Installing

To integrate MUSAP into your Android project, follow these steps:

1. Add the following dependency to your app's build.gradle file:

    implementation (files("libs/musap-[version].aar"))

2. Add the following dependencies required by the MUSAP library:

    implementation("com.squareup.okhttp3:okhttp:4.10.0")
    implementation("com.google.code.gson:gson:2.8.8")
    implementation ("org.slf4j:slf4j-api:2.0.7")
    implementation("org.bouncycastle:bcpkix-jdk15to18:1.71")
    implementation(platform("com.google.firebase:firebase-bom:32.7.0"))
    implementation("com.google.firebase:firebase-messaging")

Usage

Enabling an SSCD

Call MusapClient.init() and MusapClient.enableSscd()

public class MyApplication extends Application {

    @Override
    public void onCreate() {
        super.onCreate();
        MusapClient.init(this);
        MusapClient.enableSscd(new AndroidKeystoreSscd(this), "ANDROID");
        MusapClient.enableSscd(new YubiKeySscd(this), "YUBIKEY");
    }
}

Generating a key

Create a key generation request and call MusapClient.generateKey(). The key generation result is delivered asynchronously through the given callback.

KeyGenReq req = new KeyGenReqBuilder()
        .setActivity(this.getActivity())
        .setView(this.getView())
        .setAlias("my key")
        .setKeyAlgorithm(KeyAlgorithm.RSA_2K)
        .createKeyGenReq();

MusapClient.generateKey(sscd, req, new MusapCallback<MusapKey>() {
    @Override
    public void onSuccess(MusapKey result) {
        MLog.d("Successfully generated key " + alias);
    }

    @Override
    public void onException(MusapException e) {
        MLog.e("Failed to generate key " + alias, e);
    }
});

Signing

Select a key, create a signature request and a MusapSigner. Finally call MusapSigner.sign(). The signature result is delivered asynchronously through the given callback.

MusapKey       key = MusapClient.getKeyByUri(keyuri);
SignatureReq   req = new SignatureReqBuilder().setKey(key).setData(data).setActivity(this.getActivity()).createSignatureReq();
MusapSigner signer = new MusapSigner(key, this.getActivity());

try {
    signer.sign(data, new MusapCallback<MusapSignature>() {
        @Override
        public void onSuccess(MusapSignature mSig) {
            String signatureStr = mSig.getB64Signature();
            MLog.d("Signature successful: " + signatureStr);
        }

        @Override
        public void onException(MusapException e) {
            MLog.e("Failed to sign", e.getCause());
        }
    });
} catch (MusapException e) {
    MLog.e("Failed to sign", e.getCause());
}

Binding Keys

Select a key, create a signature request and a MusapSigner. Finally call MusapSigner.sign(). The signature result is delivered asynchronously through the given callback.

KeyBindReq req = new KeyBindReq.Builder()
        .setActivity(this.getActivity())
        .setView(this.getView())
        .setRole("personal")
        .setKeyAlias(alias)
        .createKeyBindReq();
MusapSscd sscd = this.listActiveSscds().get(0);
try {
    MusapClient.bindKey.sign(sscd, req, new MusapCallback<MusapSignature>() {
        @Override
        public void onSuccess(MusapKey key) {
            MLog.d("Bind succeeded");
        }

        @Override
        public void onException(MusapException e) {
            MLog.e("Failed to bind", e.getCause());
        }
    });
} catch (MusapException e) {
    MLog.e("Failed to bind", e.getCause());
}

Listing Keys

Select a key, create a signature request and a MusapSigner. Finally call MusapSigner.sign(). The signature result is delivered asynchronously through the given callback.

List<MusapKey> keys = MusapClient.listKeys();

for (MusapKey key : keys) {
    // get your data
}

Get enabled SSCDs

Get list of SSCDs that have been enabled MusapClient.enableSscd().

List<MusapSscd> enabledSscds = MusapClient.listEnabledSscds();

for (MusapSscd sscd : enabledSscds) {
    // get your data
}

Get active SSCDs

Get a list of SSCDs that have active keys.

List<MusapSscd> activeSscds = MusapClient.listActiveSscds();

for (MusapSscd sscd : activeSscds) {
    // get your data
}

Architecture

MUSAP Library

MUSAP Link

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.