Encryption is an essential aspect of data security. In SQL Server, one of the encryption algorithms that can be used is the Advanced Encryption Standard (AES). AES is a symmetric encryption algorithm that is widely used for securing sensitive data.

In this article, we will discuss how to use AES encryption in SQL Server to encrypt and decrypt files. We will also generate an MD5 checksum file to ensure data integrity.

Step 1: Create a C# class library project

To begin, create a new C# class library project in your preferred programming environment. You can use Visual Studio or any other suitable IDE. In this project, we will implement the AES encryption and decryption logic.

Step 2: Implement AES encryption and decryption logic

Paste the provided C# code into the class file of your project. This code contains the necessary functions to encrypt and decrypt data using AES. Make sure to understand the code and modify it according to your requirements.

Step 3: Compile the class library to an assembly

Change the target framework of the class library to .NET 3.5. This is important because SQL Server supports .NET 3.5 for CLR assemblies. Compile the project to generate the AES256.dll assembly.

Step 4: Add the assembly to the Global Assembly Cache (GAC)

Copy the compiled AES256.dll assembly to a folder on your SQL Server machine. Open a command console, navigate to the folder, and use the “gacutil” utility to add the assembly to the Global Assembly Cache (GAC). Confirm the addition of the assembly to the GAC.

Step 5: Create an SSIS project

Create a new SSIS project in Business Intelligence Development Studio (BIDS) or SQL Server Data Tools (SSDT). This project will contain the SSIS package that will utilize the AES encryption logic.

Step 6: Add a script task to the SSIS package

In the SSIS package, add a script task to the control flow. This script task will execute the AES encryption and decryption logic. Configure the script task to use the AES256.dll assembly by adding a reference to it.

Step 7: Implement the script task code

Paste the provided C# code into the script task. This code will call the AES encryption and decryption functions from the AES256.dll assembly. Modify the code to specify the input and output file paths, as well as the password and salt values.

Step 8: Execute the SSIS package

Execute the SSIS package to encrypt and decrypt the specified file. Confirm that the encrypted and decrypted files have been generated successfully. Also, verify the integrity of the encrypted file by checking the MD5 checksum in the generated md5sum.txt file.

By following these steps, you can effectively use AES encryption in SQL Server to secure your sensitive data. Remember to handle the encryption keys and passwords securely to maintain the confidentiality of your data.

Thank you for reading this article. We hope you found it helpful in understanding how to use AES encryption in SQL Server.