private void OptionValidateDocument_Click(object sender, EventArgs e)
        {
            try
            {
                string toValidate = UploadedDocumentClass.GetFileContent();

                DigitalSignatureClass signObject = new DigitalSignatureClass();
                bool isValid = signObject.ValidateDocument(toValidate);

                LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "Validating Signature");
                loadScreen.ShowDialog();

                if (isValid)
                {
                    MessageBox.Show("Signature is VALID", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
                else
                {
                    MessageBox.Show("Signature is NOT valid", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            }
            catch
            {
                MessageBox.Show("Signature is NOT valid", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        private void OptionEncryptAES_Click(object sender, EventArgs e)
        {
            SymmetricCryptography encrypterAES = new SymmetricCryptography(false);
            string contentToEncrypt            = UploadedDocumentClass.GetFileContent();
            string encrypted = encrypterAES.EncryptDocumentAES(contentToEncrypt);

            LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "AES Encryption");

            loadScreen.ShowDialog();

            SaveToTxt("helpfile_aes_encrypted", encrypted);

            outputScreen.Text = "Encrypted with AES: \r\n" + encrypted;
        }
        private void OptionSignDocument_Click(object sender, EventArgs e)
        {
            string toSign = UploadedDocumentClass.GetFileContent();

            DigitalSignatureClass signObject = new DigitalSignatureClass();
            string signedDocument            = signObject.SignDocument(toSign);

            LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "Digital Signature");

            loadScreen.ShowDialog();

            SaveToTxt("helpfile_signature", signedDocument + "\r\n" + toSign);

            outputScreen.Text  = "SHA1 digest: \r\n" + signObject.GetDigestForSign();
            outputScreen.Text += "\r\n\r\nSigned document: \r\n" + signedDocument;
        }
        private void OptionEncryptRSA_Click(object sender, EventArgs e)
        {
            AsymmetricCryptography encrypterRSA = new AsymmetricCryptography();

            encrypterRSA.GenerateKeys();
            string contentToEncrypt = UploadedDocumentClass.GetFileContent();

            string encrypted = encrypterRSA.EncryptDocumentRSA(contentToEncrypt);

            LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "RSA Encryption");

            loadScreen.ShowDialog();

            SaveToTxt("helpfile_rsa_encrypted", encrypted);

            outputScreen.Text = "Encrypted with RSA: \r\n" + encrypted;
        }
        /// <summary>
        /// Metoda koja se poziva na klik tipke za SHA1 sažimanje
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void OptionSHA1Digest_Click(object sender, EventArgs e)
        {
            string         docContent = UploadedDocumentClass.GetFileContent();
            SHADigestClass shaObject  = new SHADigestClass(docContent);

            string calculatedDigest = "";

            shaObject.GetDigest();
            calculatedDigest = shaObject.GetStringDigest();

            SaveToTxt("helpfile_sha1_digest", calculatedDigest);

            LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "SHA1 Digest");

            loadScreen.ShowDialog();

            outputScreen.Text = "SHA1 digest: \r\n" + calculatedDigest;
        }
        private void OptionDecryptAES_Click(object sender, EventArgs e)
        {
            try
            {
                SymmetricCryptography decrypterAES = new SymmetricCryptography(true);
                string contentToDecrypt            = UploadedDocumentClass.GetFileContent();
                string decrypted = decrypterAES.DecryptDocumentAES(contentToDecrypt);

                LoadingScreenForm loadScreen = new LoadingScreenForm(UploadedDocumentClass.GetFileName(), "AES Decryption");
                loadScreen.ShowDialog();

                SaveToTxt("helpfile_aes_decrypted", decrypted);

                outputScreen.Text = "Decrypted with AES: \r\n" + decrypted;
            }
            catch
            {
                MessageBox.Show("Document is not valid AES encryption", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }