MicroLite.Extensions.Cryptography

MicroLite.Extensions.Cryptography is a .NET 4.5 library which adds an extension for the MicroLite ORM Framework to encrypt and decrypt values as they are written to or read from a database.

Branch	Status
/develop
/master

Installation

Install the nuget package Install-Package MicroLite.Extensions.Cryptography

Configuration

The extension contains the DbEncryptedString class which allows you to have a property value automatically encrypted upon write to and decrypted upon read from the database.

You can use it as the property type for any mapped class by simply declaring the property as a DbEncryptedString:

public class Thing
{
    public DbEncryptedString SecureData { get; set; }
}

The DbEncryptedString class provides automatic conversion from a .NET string class so you can easily use it as follows:

var thing = new Thing { SecureData = "My Secret data..." };

Once the object is saved to the database (via ISession.InsertAsync() or ISession.UpdateAsync()) the column will contain the Base64 encoded cipher text (encrypted value). When the object is read from the database it will be decrypted and the clear text will be visible in the property.

The encrypted value will look something along the lines of MlZPjm49IKNGtOQoHAAgEa2+ycQHzXk8FIRbJ/SQ/BM=@ngWykCGsVyD/aD8ZWIhXWw==

If you want to use DbEncryptedString, you need to manually register the type converter for it. The DbEncryptedStringTypeConverter is designed to work with any implementation of the System.Security.Cryptography.SymmetricAlgorithm class. In order to achieve this, the creation of the SymmetricAlgorithm has been abstracted from the type converter.

Notice the constructor of the type converter requires an ISymmetricAlgorithmProvider:

public DbEncryptedStringTypeConverter(ISymmetricAlgorithmProvider algorithmProvider) { ... }

MicroLite.Extensions.Cryptography ships with an implementation of this interface which reads the encryption key and algorithm type from the app.config. In order to use it, add 2 values to the appsettings section:

<appSettings>
    <add key="MicroLite.DbEncryptedString.EncryptionKey" value="bru$3atheM-pey+=!a5ebr7d6Tru@E?4" />
    <add key="MicroLite.DbEncryptedString.SymmetricAlgorithm" value="AesManaged" />
</appSettings>

The SymmetricAlgorithm can be any which can be created by SymmetricAlgorithm.Create.

It is then possible to instantiate the DbEncryptedStringTypeConverter with the AppSettingSymmetricAlgorithmProvider as follows:

using MicroLite.Infrastructure;
using MicroLite.TypeConverter;

TypeConverter.Converters.Add(
    new DbEncryptedStringTypeConverter(
        new AppSettingSymmetricAlgorithmProvider()));

// Then the usual configuration for MicroLite
Configure.Fluently()...

Supported .NET Versions

The NuGet Package contains binaries compiled against (dependencies indented):

• .NET Framework 4.5
  • MicroLite 7.0.0