Need to create a encrypted .pdf file for a ReportDocument in c# with SAP Crystal Reports

Question

I need to create a .pdf file using a ReportDocument. in c#. That .pdf file need to,

Need to Encrypted with AES/CBC/PKCS5Padding
Need to use Secret Key and Initialization vector
Need to store the encrypted .pdf to the given file path.
Should not directly save the .pdf and then do the encryption later. that not valid

My idea is convert the ReportDocument to a byte array and to the task. I tried with following two methods but there are two some problems

Method 1

   internal void ExportAndSaveEncryptedPDF1(ReportDocument reportDocument, string path, byte[] key, byte[] iv)
    {
        MemoryStream reportStream = new MemoryStream();
        reportDocument.ExportToStream(ExportFormatType.PortableDocFormat, reportStream);
        byte[] reportBytes = reportStream.ToArray();
        byte[] encryptedBytes = Encrypt1(reportBytes, key, iv);
        File.WriteAllBytes(path, encryptedBytes);
    }

    public static byte[] Encrypt1(byte[] data, byte[] key, byte[] iv)
    {
        using (Aes aes = Aes.Create())
        {
            aes.Key = key;
            aes.IV = iv;
            aes.Padding = PaddingMode.PKCS7;
            ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                {
                    cryptoStream.Write(data, 0, data.Length);
                    cryptoStream.FlushFinalBlock();
                    return memoryStream.ToArray();
                }
            }
        }
    }

Problem of method 1

There is a compile error in the following line. Thea cause is, there are no any overloaded method for the two parameters. So I cannot work with report stream

reportDocument.ExportToStream(ExportFormatType.PortableDocFormat, reportStream);

Method 2

   internal void ExportAndSaveEncryptedPDF2(ReportDocument reportDocument, string path, byte[] key, byte[] iv)
    {           
        using (MemoryStream reportStream = new MemoryStream())
        {
            ExportOptions exportOptions = new ExportOptions();
            exportOptions.ExportFormatType = ExportFormatType.PortableDocFormat;
            exportOptions.ExportDestinationType = ExportDestinationType.Stream;
            exportOptions.Stream = reportStream;
            reportDocument.Export(exportOptions);
            byte[] reportBytes = reportStream.ToArray();
            byte[] encryptedBytes = Encrypt2(reportBytes, key, iv);
            File.WriteAllBytes(path, encryptedBytes);
        }
    }

    public static byte[] Encrypt2(byte[] data, byte[] key, byte[] iv)
    {
        using (Aes aes = Aes.Create())
        {
            aes.Key = key;
            aes.IV = iv;
            aes.Padding = PaddingMode.PKCS7;
            ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);
            using (MemoryStream memoryStream = new MemoryStream())
            {
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                {
                    cryptoStream.Write(data, 0, data.Length);
                    cryptoStream.FlushFinalBlock();
                    return memoryStream.ToArray();
                }
            }
        }
    }

Problem of Method 2

There are problems with following lines

ExportOptions exportOptions = new ExportOptions();
exportOptions.ExportDestinationType = ExportDestinationType.Stream;
exportOptions.Stream = reportStream;

The reason is is,

1.ExportDestinationType does not contain a definition of Stream

2.ExportOptions does not contain a definition of Stream

Anyway I need to create an encrypted .pdf to a given location in c#. Do you know a fix for this problem?

score 0 · Answer 1 · answered Jul 19 '23 at 14:03

Finally I found a way to fix this problem.

    internal void ExportAndSaveEncryptedPDF(ReportDocument reportDocument, string path, byte[] key, byte[] iv)
    {
        Stream stream = reportDocument.ExportToStream(ExportFormatType.PortableDocFormat);
        byte[] streamAsByteArray = ConvertStreamToByteArray(stream);
        byte[] encryptedByteArray = EncryptToPDF(streamAsByteArray, key, iv);
        File.WriteAllBytes(path, encryptedByteArray);
        Log.InfoFormat("Report : Successfully exported enctypted .pdf to {0}] when printout tracing", _reportXmlData.ReportConfigurationData.PDFTraceFile);
    }

    internal byte[] ConvertStreamToByteArray(Stream stram)
    {
        byte[] buffer = new byte[16 * 1024];
        using (MemoryStream ms = new MemoryStream())
        {
            int read;
            while ((read = stram.Read(buffer, 0, buffer.Length)) > 0)
            {
                ms.Write(buffer, 0, read);
            }
            return ms.ToArray();
        }
    }

    public static byte[] EncryptToPDF(byte[] data, byte[] key, byte[] iv)
    {
        using (Aes aes = Aes.Create())
        {
            aes.Key = key;
            aes.IV = iv;
            aes.Padding = PaddingMode.PKCS7;
            aes.Mode = CipherMode.CBC;
            using (MemoryStream memoryStream = new MemoryStream())
            {
                ICryptoTransform encryptor = aes.CreateEncryptor();
                using (CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                {
                    cryptoStream.Write(data, 0, data.Length);
                    cryptoStream.FlushFinalBlock();
                    return memoryStream.ToArray();
                }
            }
        }
    }

we can create a Stream and can convert it to a byte array. then after we can work with that byte array to encryption and saving

Need to create a encrypted .pdf file for a ReportDocument in c# with SAP Crystal Reports

1 Answers1