Sometimes we come across a scenario where we need to encrypt a sensitive key in appSettings section in Web.config file. This blog demonstrates the  steps to encrypt a key and read the respective key in an ASP.NET application.

I have an appsettings key that is being called from .NET application. Before we are encrypting appsettings key in web.config.

Step 1 - Adding a section in configSections in web.config
    <configSections>
    <section name="secureAppSettings" type="System.Configuration.NameValueSectionHandler, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
    </configSections

Step 2 - Add secureAppSettings section under configuration
    <secureAppSettings>
    <add key="Password" value="XXXXXXXX"/>
    </secureAppSettings>

How To Encrypt a AppSettings Key In Web.config
Step 3 - Execute command from command prompt to encrypt secureAppSettings section
Open command prompt and execute the below commands.

cd C:\Windows\Microsoft.NET\Framework\v4.0.30319
aspnet_regiis.exe -pef "secureAppSettings" "your application web config path" -prov "DataProtectionConfigurationProvider"

After execution of the above command, secure app settings section encrypted as below.

Step 4 - Accessing appsettings key from .NET code
To access the encrypted key value in code, we can write it like below.
    using System.Collections.Specialized;

    var passwordValue = "";
    var section = System.Web.Configuration.WebConfigurationManager.GetSection("secureAppSettings") as NameValueCollection;
    if (section != null && section["Password"] != null)
    {
    passwordValue = section["Password"];
    }

Excellent! We successfully encrypted to a key in appsettings in web.config. Similarly, we can do the same steps while deploying a Web application to IIS.

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