private void init(final PrivateKey privateKey, final Certificate[] chain) {
try {
Certificate certificate = chain[0];
JcaContentSignerBuilder contentSignerBuilder = new JcaContentSignerBuilder(SignatureType.SHA1_RSA.getAlgorithm());
contentSignerBuilder.setProvider(BouncyCastleProviderHelper.PROVIDER_NAME);
ContentSigner contentSigner = contentSignerBuilder.build(privateKey);
JcaDigestCalculatorProviderBuilder digestCalculatorProviderBuilder = new JcaDigestCalculatorProviderBuilder();
digestCalculatorProviderBuilder.setProvider(BouncyCastleProviderHelper.PROVIDER_NAME);
DigestCalculatorProvider digestCalculatorProvider = digestCalculatorProviderBuilder.build();