Encrypt files in SSIS

Case
Last month I did a post about encrypting certain columns with a Script Component. But I got questions about encrypting the whole file. So here are a couple of solutions.

Solutions
A) You could use an Execute Process Task to call an external executable which does the encryption for you. I personally don't like this task (feels you're a bit out of control), but it works. See this blog example and there are plenty of examples in the SSIS forum.
B) There are a couple of third party tasks that will do the encryption for you: BizCrypto, CozyRoc OpenPGP and PGP Encryption Task.
C) You could use the Script Task with some .Net coding to do it yourself.

Let's elaborate the Script Task solution:

1) Baseline Situation
The baseline situation of this case is an export from a database table to a CSV file. We will encrypt the CSV file when the data flow task is finished.

Baseline Situation

2) Variable
Create a string variable named EncryptionKey to store your encryption key in and give it a value.

Rightclick in the Control Flow

3) Script Task
Add a Script Task to the Control Flow. Give it a suitable name and connect it to the Data Flow Task.

Script Task

4) Select Variable
Edit the Script Task and select the variable EncryptionKey from step 2 as a ReadOnlyVariable.

Readonly variable

5) The Script
Hit the Edit Script button and copy the code below. The script contains an extra row to show you how you can decrypt the file again. I have created two new static methods (Encrypt and Decrypt) that will do the job. They are simplified versions of these examples at CodeProject. If you want to use these scripts commercially, make sure you read the documentation and test it thoroughly! I don't take any responsibility whatsoever.

// C# code
using System;
using System.Data;
using System.IO;                        // Added 
using System.Security.Cryptography;     // Added
using Microsoft.SqlServer.Dts.Runtime;
using System.Windows.Forms;

namespace ST_2b17b0d6160d4866b944d20ce45d0994.csproj
{
    [System.AddIn.AddIn("ScriptMain", Version = "1.0", Publisher = "", Description = "")]
    public partial class ScriptMain : Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase
    {

        #region VSTA generated code
        enum ScriptResults
        {
            Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success,
            Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
        };
        #endregion

        public void Main()
        {
            // Get the filepath of the file that needs to be encrypted. This is
            // the name of the connection manager.
            string filepath = Dts.Connections["UsersExport"].ConnectionString;

            // Determine new name: d:\folder\file.csv => d:\folder\file_ENCRYPTED.csv
            string newFilepath = filepath.Substring(0, filepath.LastIndexOf(".") -1) + "_ENCRYPTED" + filepath.Substring(filepath.LastIndexOf("."));

            // Get password from SSIS variable
            string encryptionKey = Dts.Variables["EncryptionKey"].ToString();
            
            // Create an encrypted copy of the file
            Encrypt(filepath, newFilepath, encryptionKey);

            // ADDED JUST FOR TESTING: Create a decrypted copy of the encrypted file
            Decrypt(newFilepath, newFilepath.Replace("_ENCRYPTED","_DECRYPTED"), encryptionKey);

            // Close Script Task
            Dts.TaskResult = (int)ScriptResults.Success;
        }

        // Encrypt textfile with Rijndael encryption 
        public static void Encrypt(string fileIn, string fileOut, string Password)
        {
            // Open filestream for source file
            FileStream fsIn = new FileStream(fileIn, FileMode.Open, FileAccess.Read);

            // Open filestream for encrypted file
            FileStream fsOut = new FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write);

            // Create Key and IV from the password with salt technique 
            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});

            // Create a symmetric algorithm with Rijndael 
            Rijndael alg = Rijndael.Create();

            // Set Key and IV 
            alg.Key = pdb.GetBytes(32);
            alg.IV = pdb.GetBytes(16);

            // Create a CryptoStream 
            CryptoStream cs = new CryptoStream(fsOut, alg.CreateEncryptor(), CryptoStreamMode.Write);

            // Initialize a buffer and process the input file in chunks. 
            // This is done to avoid reading the whole file (which can be huge) into memory. 
            int bufferLen = 4096;
            byte[] buffer = new byte[bufferLen];
            int bytesRead;

            do
            {
                // read a chunk of data from the input file 
                bytesRead = fsIn.Read(buffer, 0, bufferLen);

                // encrypt it 
                cs.Write(buffer, 0, bytesRead);
            } while (bytesRead != 0);

            // close everything 
            // this will also close the unrelying fsOut stream
            cs.Close();
            fsIn.Close();
        }

        // Decrypt textfile with Rijndael encryption 
        public static void Decrypt(string fileIn, string fileOut, string Password)
        {
            // Open filestream for encrypted source file
            FileStream fsIn = new FileStream(fileIn, FileMode.Open, FileAccess.Read);

            // Open filestream for decrypted file
            FileStream fsOut = new FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write);

            // Create Key and IV from the password with salt technique 
            PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] {0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76});

            // Create a symmetric algorithm with Rijndael 
            Rijndael alg = Rijndael.Create();

            // Set Key and IV 
            alg.Key = pdb.GetBytes(32);
            alg.IV = pdb.GetBytes(16);

            // Create a CryptoStream 
            CryptoStream cs = new CryptoStream(fsOut, alg.CreateDecryptor(), CryptoStreamMode.Write);

            // Initialize a buffer and process the input file in chunks. 
            // This is done to avoid reading the whole file (which can be huge) into memory.
            int bufferLen = 4096;
            byte[] buffer = new byte[bufferLen];
            int bytesRead;

            do
            {
                // read a chunk of data from the input file 
                bytesRead = fsIn.Read(buffer, 0, bufferLen);

                // Decrypt it 
                cs.Write(buffer, 0, bytesRead);
            } while (bytesRead != 0);

            // close everything 
            // this will also close the unrelying fsOut stream 
            cs.Close(); 
            fsIn.Close();
        }
    }
}

Or VB.Net

' VB.Net code
Imports System
Imports System.Data
Imports System.IO                       ' Added
Imports System.Security.Cryptography    ' Added 
Imports System.Math
Imports Microsoft.SqlServer.Dts.Runtime

<System.AddIn.AddIn("ScriptMain", Version:="1.0", Publisher:="", Description:="")> _
<System.CLSCompliantAttribute(False)> _
Partial Public Class ScriptMain
 Inherits Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTARTScriptObjectModelBase

 Enum ScriptResults
  Success = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Success
  Failure = Microsoft.SqlServer.Dts.Runtime.DTSExecResult.Failure
 End Enum
 

 Public Sub Main()
        ' Get the filepath of the file that needs to be encrypted. This is
        ' the name of the connection manager.
        Dim filepath As String = Dts.Connections("UsersExport").ConnectionString

        ' Determine new name: d:\folder\file.csv => d:\folder\file_ENCRYPTED.csv
        Dim newFilepath As String = filepath.Substring(0, filepath.LastIndexOf(".") - 1) & "_ENCRYPTED" & filepath.Substring(filepath.LastIndexOf("."))

        ' Get password from SSIS variable
        Dim encryptionKey As String = Dts.Variables("EncryptionKey").ToString()

        ' Create an encrypted copy of the file
        Encrypt(filepath, newFilepath, encryptionKey)

        ' ADDED JUST FOR TESTING: Create a decrypted copy of the encrypted file
        Decrypt(newFilepath, newFilepath.Replace("_ENCRYPTED", "_DECRYPTED"), encryptionKey)

        ' Close Script Task
        Dts.TaskResult = ScriptResults.Success
 End Sub

    ' Encrypt textfile with Rijndael encryption 
    Public Shared Sub Encrypt(ByVal fileIn As String, ByVal fileOut As String, ByVal Password As String)
        ' Open filestream for source file
        Dim fsIn As New FileStream(fileIn, FileMode.Open, FileAccess.Read)

        ' Open filestream for encrypted file
        Dim fsOut As New FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write)

        ' Create Key and IV from the password with salt technique 
        Dim pdb As New PasswordDeriveBytes(Password, New Byte() {&H49, &H76, &H61, &H6E, &H20, &H4D, &H65, &H64, &H76, &H65, &H64, &H65, &H76})

        ' Create a symmetric algorithm with Rijndael 
        Dim alg As Rijndael = Rijndael.Create()

        ' Set Key and IV 
        alg.Key = pdb.GetBytes(32)
        alg.IV = pdb.GetBytes(16)

        ' Create a CryptoStream 
        Dim cs As New CryptoStream(fsOut, alg.CreateEncryptor(), CryptoStreamMode.Write)

        ' Initialize a buffer and process the input file in chunks. 
        ' This is done to avoid reading the whole file (which can be huge) into memory. 
        Dim bufferLen As Integer = 4096
        Dim buffer As Byte() = New Byte(bufferLen - 1) {}
        Dim bytesRead As Integer

        Do
            ' read a chunk of data from the input file 
            bytesRead = fsIn.Read(buffer, 0, bufferLen)

            ' encrypt it 
            cs.Write(buffer, 0, bytesRead)
        Loop While bytesRead <> 0

        ' close everything 
        ' this will also close the unrelying fsOut stream
        cs.Close()
        fsIn.Close()
    End Sub

    ' Decrypt textfile with Rijndael encryption 
    Public Shared Sub Decrypt(ByVal fileIn As String, ByVal fileOut As String, ByVal Password As String)
        ' Open filestream for encrypted source file
        Dim fsIn As New FileStream(fileIn, FileMode.Open, FileAccess.Read)

        ' Open filestream for decrypted file
        Dim fsOut As New FileStream(fileOut, FileMode.OpenOrCreate, FileAccess.Write)

        ' Create Key and IV from the password with salt technique 
        Dim pdb As New PasswordDeriveBytes(Password, New Byte() {&H49, &H76, &H61, &H6E, &H20, &H4D, &H65, &H64, &H76, &H65, &H64, &H65, &H76})

        ' Create a symmetric algorithm with Rijndael 
        Dim alg As Rijndael = Rijndael.Create()

        ' Set Key and IV 
        alg.Key = pdb.GetBytes(32)
        alg.IV = pdb.GetBytes(16)

        ' Create a CryptoStream 
        Dim cs As New CryptoStream(fsOut, alg.CreateDecryptor(), CryptoStreamMode.Write)

        ' Initialize a buffer and process the input file in chunks. 
        ' This is done to avoid reading the whole file (which can be huge) into memory.
        Dim bufferLen As Integer = 4096
        Dim buffer As Byte() = New Byte(bufferLen - 1) {}
        Dim bytesRead As Integer

        Do
            ' read a chunk of data from the input file 
            bytesRead = fsIn.Read(buffer, 0, bufferLen)

            ' Decrypt it 
            cs.Write(buffer, 0, bytesRead)
        Loop While bytesRead <> 0

        ' close everything 
        ' this will also close the unrelying fsOut stream 
        cs.Close()
        fsIn.Close()
    End Sub
End Class

6) The result
See the result of encryption and decryption.

Good luck reading that encrypted file

Note: This example uses Rijndael, but there are more methods available in .Net