AspNetCore.Docs/aspnetcore/security/data-protection/configuration/non-di-scenarios.md

title	author	description	ms.author	ms.date	uid
Non-DI aware scenarios for Data Protection in ASP.NET Core	tdykstra	Learn how to support data protection scenarios where you can't or don't want to use a service provided by dependency injection.	tdykstra	10/14/2016	security/data-protection/configuration/non-di-scenarios

Non-DI aware scenarios for Data Protection in ASP.NET Core

By Rick Anderson

The ASP.NET Core Data Protection system is normally added to a service container and consumed by dependent components via dependency injection (DI). However, there are cases where this isn't feasible or desired, especially when importing the system into an existing app.

To support these scenarios, the Microsoft.AspNetCore.DataProtection.Extensions package provides a concrete type, xref:Microsoft.AspNetCore.DataProtection.DataProtectionProvider, which offers a simple way to use Data Protection without relying on DI. The DataProtectionProvider type implements xref:Microsoft.AspNetCore.DataProtection.IDataProtectionProvider. Constructing DataProtectionProvider only requires providing a xref:System.IO.DirectoryInfo instance to indicate where the provider's cryptographic keys should be stored, as seen in the following code sample:

[!code-csharp]

By default, the DataProtectionProvider concrete type doesn't encrypt raw key material before persisting it to the file system. This is to support scenarios where the developer points to a network share and the Data Protection system can't automatically deduce an appropriate at-rest key encryption mechanism.

Additionally, the DataProtectionProvider concrete type doesn't isolate apps by default. All apps using the same key directory can share payloads as long as their purpose parameters match.

The xref:Microsoft.AspNetCore.DataProtection.DataProtectionProvider constructor accepts an optional configuration callback that can be used to adjust the behaviors of the system. The sample below demonstrates restoring isolation with an explicit call to xref:Microsoft.AspNetCore.DataProtection.DataProtectionBuilderExtensions.SetApplicationName%2A. The sample also demonstrates configuring the system to automatically encrypt persisted keys using Windows DPAPI. If the directory points to a UNC share, you may wish to distribute a shared certificate across all relevant machines and to configure the system to use certificate-based encryption with a call to xref:Microsoft.AspNetCore.DataProtection.DataProtectionBuilderExtensions.ProtectKeysWithCertificate%2A.

[!code-csharp]

[!TIP] Instances of the DataProtectionProvider concrete type are expensive to create. If an app maintains multiple instances of this type and if they're all using the same key storage directory, app performance might degrade. If you use the DataProtectionProvider type, we recommend that you create this type once and reuse it as much as possible. The DataProtectionProvider type and all xref:Microsoft.AspNetCore.DataProtection.IDataProtector instances created from it are thread-safe for multiple callers.