# Message body encryption

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This sample demonstrates how to use `IMutateTransportMessages` to encrypt and decrypt the binary representation of a message as it passes through the pipeline.

Running the solution starts two console applications. `Endpoint1` encrypts a message and sends it and `Endpoint2` receives the encrypted message and decrypts it.

### Endpoint1 output

```
Message sent.
```

### Endpoint2 output

```
CompleteOrderHandler Received CompleteOrder with credit card number 123-456-789
```


## Code walk-through


### Message contract

The `Shared` project contains `CompleteOrder.cs`, which defines the message contract:

<!-- snippet: Message -->

```cs
public class CompleteOrder : IMessage
{
    public string CreditCard { get; set; }
}
```

<!-- endsnippet -->

Note that a custom property type is not required.


### Encryption configuration

Encryption is enabled by calling an extension method in `Program.cs` in both `Endpoint1` and `Endpoint2`:

<!-- snippet: RegisterMessageEncryptor -->

```cs
endpointConfiguration.RegisterMessageEncryptor();
```

<!-- endsnippet -->

The extension method is in `Shared/EncryptionExtensions.cs`:

<!-- snippet: MessageEncryptorExtension -->

```cs
public static class EndpointConfigurationExtensions
{
    public static void RegisterMessageEncryptor(this EndpointConfiguration endpointConfiguration)
    {
        endpointConfiguration.RegisterMessageMutator(new MessageEncryptor());
    }
}
```

<!-- endsnippet -->

The mutator is in `Shared/MessageEncryptor.cs`:

> [!WARNING]
> This is for demonstration purposes and is not true encryption. It is only doing a byte array reversal to illustrate the API. In a production system, encryption should be performed used the [.NET Framework Cryptography Model](https://learn.microsoft.com/en-us/dotnet/standard/security/cryptography-model) or some other secure mechanism.

<!-- snippet: Mutator -->

```cs
public class MessageEncryptor :
    IMutateIncomingTransportMessages,
    IMutateOutgoingTransportMessages
{

    public Task MutateIncoming(MutateIncomingTransportMessageContext context)
    {
        context.Body = context.Body.ToArray().Reverse().ToArray();
        return Task.CompletedTask;
    }

    public Task MutateOutgoing(MutateOutgoingTransportMessageContext context)
    {
        context.OutgoingBody = context.OutgoingBody.ToArray().Reverse().ToArray();
        return Task.CompletedTask;
    }
}
```

<!-- endsnippet -->