ProtectedData Class

July 28, 2014

Provides methods for encrypting and decrypting data. This class cannot be inherited.

System.Object
  System.Security.Cryptography.ProtectedData

Namespace:  System.Security.Cryptography
Assembly:  mscorlib.Extensions (in mscorlib.Extensions.dll)

public static class ProtectedData

The ProtectedData type exposes the following members.

  NameDescription
Public methodStatic memberProtectEncrypts the data in a specified byte array and returns a byte array that contains the encrypted data.
Public methodStatic memberUnprotectDecrypts the data in a specified byte array and returns a byte array that contains the decrypted data.
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This class provides access to the Data Protection API (DPAPI). This is a service that is provided by the operating system and does not require additional libraries. It provides protection using the user or machine credentials to encrypt or decrypt data.

 In Windows Phone, both the user and machine credentials are used to encrypt or decrypt data.

The class consists of two wrappers for the unmanaged DPAPI, Protect and Unprotect. These two methods can be used to encrypt and decrypt data such as passwords, keys, and connection strings.

If you use these methods during impersonation, you may receive the following error: "Key not valid for use in specified state." This occurs because the DPAPI stores the key data in user profiles. If the profile is not loaded, DPAPI won’t be able to perform the decryption. To prevent this error, load the profile of the user you want to impersonate before calling either method. Using DPAPI with impersonation can incur significant complication and requires careful design choices.

For information about how to encrypt and decrypt data in a Windows Phone application, see How to: Encrypt Data in a Windows Phone Application.

TopicLocation
How to: Use Data Protection.NET Framework: Security
How to: Use Data Protection.NET Framework: Security

Windows Phone OS

Supported in: 8.1, 8.0, 7.1

Windows Phone

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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