How can I construct a java.security.PublicKey object from a base64 encoded string?

Question

I have a bse64encoded string Public key from external source (Android Store) and I need to use it to verify signed content. How can I convert the string into an instance of the java.security.PublicKey interface. I am on Java 6 if that makes a difference.

The key is (probably) generated using standard java lib and not bouncy castle (its from a remote team so I am not sure). Their sample code says to use Security.generatePublicKey(base64EncodedPublicKey); but the Security object in standard java has no such method.

Answer 1

Code for the above answer

public static PublicKey getKey(String key){
    try{
        byte[] byteKey = Base64.decode(key.getBytes(), Base64.DEFAULT);
        X509EncodedKeySpec X509publicKey = new X509EncodedKeySpec(byteKey);
        KeyFactory kf = KeyFactory.getInstance("RSA");

        return kf.generatePublic(X509publicKey);
    }
    catch(Exception e){
        e.printStackTrace();
    }

    return null;
}