This is a pure Java implementation of the ykpiv library created by Yubico. Unlike other ports of the ykpiv library to other languages, this is a complete port of the ykpiv library and not a wrapper around the native library. It is implemented on top of the Java Smart Card I/O API, so it does not include any JNI component. Therefore, this library should be immediately usable on all platforms that support a complete JRE.

At present, the easiest way to include this library is by referencing the following bintray repo:

repositories {
    maven {
        url 'https://dl.bintray.com/jackofmosttrades/maven/'
    }
}

dependencies {
    compile 'com.github.jackofmosttrades:ykpiv:1.0'
}

The main class for this library is YkPiv. Upon construction it creates a connection to the yubikey, and so you should close the YkPiv object to disconnect.

This is a brief example of using the library to generate a key in the Authentication slot, and sign some data with it.

try (YkPiv ykPiv = new YkPiv()) {
    ykPiv.authenticate(YkPiv.DEFAULT_MGMT_KEY);
    PublicKey publicKey = ykPiv.generateKey(KeySlot.AUTHENTICATION, keyAlgorithm, PinPolicy.NEVER, TouchPolicy.NEVER);
    ykPiv.login(YkPiv.DEFAULT_PIN);
    byte[] signature = ykPiv.hashAndSign(data, hashAlgorithm, keyAlgorithm, KeySlot.AUTHENTICATION);
}

You can use the yubikey PIV application to hold the private key used for TLS connections (on either the server or client side). The SSLConnectionTest shows an example of how to do this. In short:

Security.addProvider(new YkPivSecurityProvider());

SSLContext sslContext = SSLContext.getInstance("TLS");
KeyManagerFactory kmf = KeyManagerFactory.getInstance(YkPivKeyManagerFactory.ALGORITHM);
kmf.init(YkPivKeyManagerFactory.initParameters(KeySlot.AUTHENTICATION));
sslContext.init(kmf.getKeyManagers(), null, null);

// Use this SSLContext to either create a socket directly, or e.g. with an HttpsUrlConnection
HttpsURLConnection connection = (HttpsURLConnection) new URL("https://example.com").openConnection();
connection.setSSLSocketFactory(sslContext.getSocketFactory());