17 Responses for "How rdp passwords are encrypted 2"

1. Shankar March 11th, 2008 at 17:56 1

   Hi,
   I tried using the .NET wrapper provided by MS and using the help. But your tool is not able to decrypt the same. Could you please post the code for the encryption?

2. Mul March 13th, 2008 at 16:54 2

   Is it possible to generate a hash for another user / Sid ? – I have a requirement using HP thin clients to generate the appropriate hash to insert in default.rdp file – it works for Adminstrator user on the thin client – but obviously not for the User account.

3. Dominique Descat May 15th, 2008 at 21:04 3

   Hi,
   I would like distribute the same file.rdp on my 2 different XP WS (with the same pwd).
   Please, could you said me how to generate the ‘passord 51:b:’ with VBscript?
   Thank for your reply.
   Regards.
   Dominik

4. Remko May 16th, 2008 at 12:48 4

   @Dominique: This is not possible with VBS since there is no COM object that supports CryptProtect Data api.
   You would either have to create a commandline encryption tool or a com enabled one to encrypt passwords with vbs.

5. Dominique Descat May 17th, 2008 at 13:54 5

   Hi,
   In that case, is your rdp2.exe usable from a command line with parameters?
   Best regards.
   Dominik

6. Dominique Descat May 19th, 2008 at 14:56 6

   Remko, thanks for your Web site, thanks also to Justin Shepard for the translation into VB.
   I have change something’s within his code and adapted the sub main to create an executable object with VB express 2005 (please transfer this news to Jeremy…)
   Concerning my main code, I use 2 parameters (arguments): input file name & output file name. At the end of the encryption, the 1329 bytes are completed with the end of the encryption of 256 spaces.
   ####################################
   Imports System
   Imports System.IO
   Imports System.Text
   Imports System.Runtime.InteropServices
   Imports System.ComponentModel
   Imports Microsoft.VisualBasic

   Public Module RdpEncrypt

   Public Class DPAPI
   _
   Private Shared Function CryptProtectData( _
   ByRef pPlainText As DATA_BLOB, _
   ByVal szDescription As String, _
   ByRef pEntropy As DATA_BLOB, _
   ByVal pReserved As IntPtr, _
   ByRef pPrompt As CRYPTPROTECT_PROMPTSTRUCT, _
   ByVal dwFlags As Integer, _
   ByRef pCipherText As DATA_BLOB _
   ) As Boolean
   End Function

   _
   Private Shared Function CryptUnprotectData( _
   ByRef pCipherText As DATA_BLOB, _
   ByRef pszDescription As String, _
   ByRef pEntropy As DATA_BLOB, _
   ByVal pReserved As IntPtr, _
   ByRef pPrompt As CRYPTPROTECT_PROMPTSTRUCT, _
   ByVal dwFlags As Integer, _
   ByRef pPlainText As DATA_BLOB _
   ) As Boolean
   End Function

   _
   Friend Structure DATA_BLOB
   Public cbData As Integer
   Public pbData As IntPtr
   End Structure

   _
   Friend Structure CRYPTPROTECT_PROMPTSTRUCT
   Public cbSize As Integer
   Public dwPromptFlags As Integer
   Public hwndApp As IntPtr
   Public szPrompt As String
   End Structure

   Private Const CRYPTPROTECT_UI_FORBIDDEN As Integer = 1
   Private Const CRYPTPROTECT_LOCAL_MACHINE As Integer = 4

   Private Shared Sub InitPrompt _
   ( _
   ByRef ps As CRYPTPROTECT_PROMPTSTRUCT _
   )
   ps.cbSize = Marshal.SizeOf(GetType(CRYPTPROTECT_PROMPTSTRUCT))
   ps.dwPromptFlags = 0
   ps.hwndApp = IntPtr.Zero
   ps.szPrompt = Nothing
   End Sub

   Private Shared Sub InitBLOB _
   ( _
   ByVal data As Byte(), _
   ByRef blob As DATA_BLOB _
   )
   ‘ Use empty array for null parameter.
   If data Is Nothing Then
   data = New Byte(0) {}
   End If

   ‘ Allocate memory for the BLOB data.
   blob.pbData = Marshal.AllocHGlobal(data.Length)

   ‘ Make sure that memory allocation was successful.
   If blob.pbData.Equals(IntPtr.Zero) Then
   Throw New Exception( _
   “Unable to allocate data buffer for BLOB structure.”)
   End If

   ‘ Specify number of bytes in the BLOB.
   blob.cbData = data.Length
   Marshal.Copy(data, 0, blob.pbData, data.Length)
   End Sub

   Public Enum KeyType
   UserKey = 1
   MachineKey
   End Enum

   Private Shared defaultKeyType As KeyType = KeyType.UserKey

   Public Shared Function Encrypt _
   ( _
   ByVal keyType As KeyType, _
   ByVal plainText As String, _
   ByVal entropy As String, _
   ByVal description As String _
   ) As String
   If plainText Is Nothing Then
   plainText = String.Empty
   End If
   If entropy Is Nothing Then
   entropy = String.Empty
   End If

   Dim result As Byte()
   Dim encrypted As String = “”
   Dim i As Integer
   result = Encrypt(keyType, _
   Encoding.Unicode.GetBytes(plainText), _
   Encoding.Unicode.GetBytes(entropy), _
   description)
   For i = 0 To result.Length – 1
   encrypted = encrypted & Convert.ToString(result(i), 16).PadLeft(2, “0”).ToUpper()
   Next
   Return encrypted.ToString()
   End Function

   Public Shared Function Encrypt _
   ( _
   ByVal keyType As KeyType, _
   ByVal plainTextBytes As Byte(), _
   ByVal entropyBytes As Byte(), _
   ByVal description As String _
   ) As Byte()
   If plainTextBytes Is Nothing Then
   plainTextBytes = New Byte(0) {}
   End If

   If entropyBytes Is Nothing Then
   entropyBytes = New Byte(0) {}
   End If

   If description Is Nothing Then
   description = String.Empty
   End If

   Dim plainTextBlob As DATA_BLOB = New DATA_BLOB
   Dim cipherTextBlob As DATA_BLOB = New DATA_BLOB
   Dim entropyBlob As DATA_BLOB = New DATA_BLOB

   Dim prompt As _
   CRYPTPROTECT_PROMPTSTRUCT = New CRYPTPROTECT_PROMPTSTRUCT
   InitPrompt(prompt)

   Try
   Try
   InitBLOB(plainTextBytes, plainTextBlob)
   Catch ex As Exception
   Throw New Exception(“Cannot initialize plaintext BLOB.”, ex)
   End Try

   Try
   InitBLOB(entropyBytes, entropyBlob)
   Catch ex As Exception
   Throw New Exception(“Cannot initialize entropy BLOB.”, ex)
   End Try

   Dim flags As Integer = CRYPTPROTECT_UI_FORBIDDEN

   If keyType = keyType.MachineKey Then
   flags = flags Or (CRYPTPROTECT_LOCAL_MACHINE)
   End If

   Dim success As Boolean = CryptProtectData( _
   plainTextBlob, _
   description, _
   entropyBlob, _
   IntPtr.Zero, _
   prompt, _
   flags, _
   cipherTextBlob)

   If Not success Then
   Dim errCode As Integer = Marshal.GetLastWin32Error()

   Throw New Exception(“CryptProtectData failed.”, _
   New Win32Exception(errCode))
   End If

   Dim cipherTextBytes(cipherTextBlob.cbData) As Byte

   Marshal.Copy(cipherTextBlob.pbData, cipherTextBytes, 0, _
   cipherTextBlob.cbData)

   Return cipherTextBytes
   Catch ex As Exception
   Throw New Exception(“DPAPI was unable to encrypt data.”, ex)
   Finally
   If Not (plainTextBlob.pbData.Equals(IntPtr.Zero)) Then
   Marshal.FreeHGlobal(plainTextBlob.pbData)
   End If

   If Not (cipherTextBlob.pbData.Equals(IntPtr.Zero)) Then
   Marshal.FreeHGlobal(cipherTextBlob.pbData)
   End If

   If Not (entropyBlob.pbData.Equals(IntPtr.Zero)) Then
   Marshal.FreeHGlobal(entropyBlob.pbData)
   End If
   End Try
   End Function

   End Class

   Sub Main(ByVal args() As String)
   Try
   Dim INfilename As String = args(0) ‘Input file with string without CrLf
   Dim OUTfilename As String = args(1) ‘Output file
   Dim EncryptedText As String
   Dim TextToEncrypt As String
   Dim EncryptedBlank As String
   Dim BlankToEncrypt As String = Space(256)

   TextToEncrypt = File.ReadAllText(INfilename)

   EncryptedText = DPAPI.Encrypt(DPAPI.KeyType.MachineKey, TextToEncrypt, Nothing, “psw”)
   EncryptedBlank = DPAPI.Encrypt(DPAPI.KeyType.MachineKey, BlankToEncrypt, Nothing, “psw”)

   File.WriteAllText(OUTfilename, EncryptedText & _
   Right(EncryptedBlank, 1329 – Len(EncryptedText))) ‘Encrypted blank to complete to 1329

   Catch ex As Exception
   While Not (ex Is Nothing)
   Console.WriteLine(ex.Message)
   ex = ex.InnerException
   End While
   End Try
   End Sub

   End Module
   ####################################
   Regards.
   Dominik

7. Gareth June 11th, 2008 at 17:06 7

   Hi Remko,

   In your original post in the comments you wrote:
   “I will write a new demo app to accompany the article that encrypts the full length password and can encrypt password that are valid for machine instead of user.
   This makes it possible (eg) to publish an rdp connection.”

   I’m just wondering if this is the app you were talking about. I tried to encrypt a password using the tool but didn’t see any option for machine vs. user; I tried it anyway but it doesn’t seem to work for any other user that signs on to the machine besides the one the password was encrypted under.

   Any tips? Basically what I’m trying to do is make an RDP file that I can save under All Users\Desktop and any user who signs in can use it to connect to another machine using a single username/password. I tried your LaunchRDP utility however the missing ‘toolbar’ is an issue for me (users need to be able to minimize the remote desktop window)

   Thanks!

8. Jignesh July 5th, 2008 at 16:38 8

   Hello Remko,

   Can you please give me code in C++ which does password encryption same as RDP does?

   I am working on very urgent requirement.

   It will be greate if you help me.

   Thanks

   Jignesh

9. Lokesh October 13th, 2008 at 9:04 9

   Hi Remko !!
   Can you please provide the source code in VC++ 6.0/mfc for the encryption/decryption tool that you have used in your ‘Remote Desktop Password Encryption & Decryption Tool (395)’.

   Thanks in advance 🙂

10. Fedro ponce de leon November 1st, 2008 at 17:40 10

    Is there any VC++ code available?

11. Angeliccare December 2nd, 2008 at 18:23 11

    Dominique Descat, if you will not be against, I would use your code for one of sourceforge projects: RDPman and it’s derivate?

    Thanks.

    (In e-mail it’s not .ur – shold be .ru, thanks for understanding)

12. Nullstring April 5th, 2009 at 4:42 12

    Hey thanks for this info. Learned a lot from you.

    I have done the same thing in C# but using DataProtection found in http://msdn.microsoft.com/en-us/library/aa302402.aspx#secnetht07_topic4

    You can download the Encrypt/Decrypt sample here.
    http://multirdpc.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=25591#ReleaseFiles

13. Tim McGrath September 9th, 2009 at 21:19 13

    I used this tool to encrypt my password and put it in an RDP file.

    It seems that Windows (XP Pro SP3) ignores the username and password entries that I put in the RDP file and will only use the credentials stored in the registry. It doesn’t matter whether I launch the RDP by double-clicking it or launching it using mstsc from a command prompt.

    Does anyone know how to get Windows use the credentials I have stored in the RDP file? Is it because of the version of mstsc (and supporting files) that I am using? A policy? Thanks a lot

14. maurizio November 9th, 2009 at 21:03 14

    I want automated the file creation with .rdp extension for remote desktop and your program is very good but in my vb6 program the call at your program is not the good way.

    is not possible for you create an rdp.dll with the encrypt function only ????

    Best regards

15. Decrypt Remote Desktop Mobile password | Windows CE Programming February 19th, 2010 at 6:25 15

    […] I found the article about decrypting saved RDP passwords at http://www.jaysonragasa.net/post/EncryptDecrypt-RDP-Password.aspx and https://www.remkoweijnen.nl/blog/2008/03/02/how-rdp-passwords-are-encrypted-2/. […]

16. meg43tr44gi joe December 7th, 2011 at 21:00 16

    Thank you for another informative site. Where else may just I am getting that type of info written in such a perfect approach? I have a mission that I’m just now working on, and I’ve been at the look out for such info.

17. Santosh Patil June 5th, 2015 at 8:30 17

    Hi Remko,

    I have following question:
    If I created the MSTSC encrypted password for “secrettext” password on Desktop Machine-1, somehow I cannot use this encrypted password on Desktop Machine-2. Can we generate the MSTSC encrypted password for “secrettext” password, which will be work on different windows machines? Is there any API or any combination in “CryptProtectData” API to do this?
    It’s very urgent, if you guide me in these case then it will be great help for me.
    Thanks in advance.

    Thanks & regards,
    Santosh Patil