Provider provider = null;
        if (useBouncyCastleProvider) {
            provider = new BouncyCastleProvider();
            Security.addProvider(provider);
        }

        // Message Digest
        Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());

        FileInputStream fin = new FileInputStream(FILENAME_CER);
        CertificateFactory f = CertificateFactory.getInstance("X.509");
        X509Certificate certificate = (X509Certificate) f.generateCertificate(fin);
        PublicKey publickey = certificate.getPublicKey();

        String hashingAlgorithm = "SHA-256";

        MessageDigest messageDigestProvider = null;
        if (null != provider) {
            messageDigestProvider = MessageDigest.getInstance(hashingAlgorithm, provider);
        } else {
            messageDigestProvider = MessageDigest.getInstance(hashingAlgorithm);
        }
        messageDigestProvider.update(firmaCompuesta.getBytes());

        byte[] hash = messageDigestProvider.digest();

        DigestAlgorithmIdentifierFinder hashAlgorithmFinder = new DefaultDigestAlgorithmIdentifierFinder();
        AlgorithmIdentifier hashingAlgorithmIdentifier = hashAlgorithmFinder.find(hashingAlgorithm);

        DigestInfo digestInfo = new DigestInfo(hashingAlgorithmIdentifier, hash);
        byte[] hashToEncrypt = digestInfo.getEncoded();

        // Crypto
        // You could also use "RSA/ECB/PKCS1Padding" for both the BC and SUN Providers.
        Cipher encCipher = null;
        if (null != provider) {
            encCipher = Cipher.getInstance("RSA/NONE/PKCS1Padding", provider);
        } else {
            encCipher = Cipher.getInstance("RSA");
        }

        //=============== JEMJ CIFRADO DESDE .CER =============
        encCipher.init(Cipher.ENCRYPT_MODE, publickey);

        byte[] encrypted = encCipher.doFinal(hashToEncrypt);

        System.out.println("nnHash and Encryption Output : nn");
        //
        encodedBytes = Base64.encodeBase64(encrypted);
        encodedBytesStr = new String(encodedBytes);
        //
        System.out.println(encodedBytesStr);