---Java
	//I used this on Android
	//before you proceed, you need to ensure your private key is PKCS8 since that is what can be read natively in java. 
	//If your key begins with -----BEGIN RSA PRIVATE KEY-----, the it is ssleay and you need to convert it using the openssl command below
	//openssl pkcs8 -topk8 -inform pem -in ssleay-private-key.key -outform pem -nocrypt -out pkcs8-private-key.pem
    
	final private static String RSA_PRIVATE_KEY =
            "-----BEGIN PRIVATE KEY-----\n"  +
            "MI...\n" +
            "2...\n" +
            "HPt...\n" +
			...
            "v3...\n" +
            "-----END PRIVATE KEY-----";




    public static byte[] decrypt(String key) throws Exception {
        String privKeyPEM = RSA_PRIVATE_KEY.replace("-----BEGIN PRIVATE KEY-----\n", "");
        privKeyPEM = privKeyPEM.replace("-----END PRIVATE KEY-----", "");
        byte [] encoded = Base64.decode(privKeyPEM, Base64.DEFAULT);


        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        PrivateKey privKey = kf.generatePrivate(keySpec);

        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", "BC");
        cipher.init(Cipher.DECRYPT_MODE, privKey);

        byte[] decodedStr           = Base64.decode(key, Base64.DEFAULT);
        byte[] plainText            = cipher.doFinal(decodedStr);

        return plainText;
    }