Search
Module:
Directory

   Desktop Functions:

   Smart Device Functions:


Show Recent Changes
Subscribe (RSS)
Misc. Pages
Comments
FAQ
Helpful Tools
Playground
Suggested Reading
Website TODO List
Download Visual Studio Add-In

CryptUnprotectData (crypt32)
 
.
Summary
The CryptUnprotectData function decrypts and does an integrity check of the data in a DATA_BLOB structure. Usually, only a user with the same logon credentials as the encrypter can decrypt the data. In addition, the encryption and decryption must be done on the same computer.

C# Signature:

[
DllImport("Crypt32.dll",
SetLastError=true,
CharSet=System.Runtime.InteropServices.CharSet.Auto)
]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CryptUnprotectData(
    ref DATA_BLOB pDataIn,
    StringBuilder szDataDescr,
    String szDataDescr,
    ref DATA_BLOB pOptionalEntropy,
    IntPtr pvReserved,
    ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
    CryptProtectFlags dwFlags,
    ref DATA_BLOB pDataOut
);

VB .NET Signature:

<DllImport("Crypt32.dll", SetLastError:=True, CharSet:=System.Runtime.InteropServices.CharSet.Auto)> _
Private Shared Function CryptUnprotectData _
( _
     ByRef pDataIn As DATA_BLOB, _
     ByVal szDataDescr As StringBuilder, _
     ByVal szDataDescr As String, _
     ByRef pOptionalEntropy As DATA_BLOB, _
     ByVal pvReserved As IntPtr, _
     ByRef pPromptStruct As CRYPTPROTECT_PROMPTSTRUCT, _
     ByVal dwFlags As Integer, _
     ByRef pDataOut As DATA_BLOB _
) As Boolean
End Function

See also:

DATA_BLOB

CRYPTPROTECT_PROMPTSTRUCT

CryptProtectFlags

CryptProtectData

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

How To Create a DPAPI Library: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/secmod/html/secmod21.asp

Alternative Managed API:

In .NET v2.0, the ProtectedData.Unprotect method provides the same functionality.

In the upcoming .NET v2.0, the ProtectData class will provide the same functionality.

Documentation

Please edit this page!

Do you have...

  • helpful tips or sample code to share for using this API in managed code?
  • corrections to the existing content?
  • variations of the signature you want to share?
  • additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).

 
Access PInvoke.net directly from VS:
Terms of Use
Edit This Page
Find References
Show Printable Version
Revisions