GetTlsCipherSuite Method

'Declaration
 
Public Function GetTlsCipherSuite() As DicomTlsCipherSuiteType

<StructLayout(LayoutKind.Sequential)> _
     Public Structure MSG
         Public hwnd As IntPtr
         Public message As UInteger
         Public wParam As IntPtr
         Public lParam As IntPtr
         Public time As UInteger
         Public p As System.Drawing.Point
     End Structure
     Public Enum WaitReturn
         Complete
         Timeout
     End Enum

     Private Class Utils
      <DllImport("user32.dll")> _
      Shared Function PeekMessage(<System.Runtime.InteropServices.Out()> ByRef lpMsg As MSG, ByVal hWnd As IntPtr, ByVal wMsgFilterMin As UInteger, _
                                     ByVal wMsgFilterMax As UInteger, ByVal wRemoveMsg As UInteger) As <MarshalAs(UnmanagedType.Bool)> Boolean
      End Function

         <DllImport("user32.dll")> _
         Shared Function TranslateMessage(ByRef lpMsg As MSG) As Boolean
         End Function
         <DllImport("user32.dll")> _
         Shared Function DispatchMessage(ByRef lpmsg As MSG) As IntPtr
         End Function

         Private Const PM_REMOVE As UInteger = 1

         Public Shared Function WaitForComplete(ByVal mill As Double, ByVal wh As WaitHandle) As WaitReturn
             Dim goal As TimeSpan = New TimeSpan(DateTime.Now.AddMilliseconds(mill).Ticks)

             Do
                 Dim msg As MSG = New MSG()

                 If PeekMessage(msg, IntPtr.Zero, 0, 0, PM_REMOVE) Then
                     TranslateMessage(msg)
                     DispatchMessage(msg)
                 End If

                 If wh.WaitOne(New TimeSpan(0, 0, 0), False) Then
                     Return WaitReturn.Complete
                 End If

                 If goal.CompareTo(New TimeSpan(DateTime.Now.Ticks)) < 0 Then
                     Return WaitReturn.Timeout
                 End If

             Loop While True
         End Function
     End Class

     '
     ' Secure client (TLS)
     '
     Private Class Client : Inherits DicomNet
         Private waitEvent As AutoResetEvent = New AutoResetEvent(False)
      Private clientPEM As String = Path.Combine(LEAD_VARS.ImagesDir, "client.pem")

      Public Sub New()
         MyBase.New(Nothing, DicomNetSecurityeMode.Tls)
         SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWithDesCbcSha)
         SetTlsClientCertificate(clientPEM, DicomTlsCertificateType.Pem, Nothing)

         'Over here we can get detailed information about the Cipher Suite
         ' Can also call GetTlsCipherSuiteByIndex
         Dim cipherSuite As DicomTlsCipherSuiteType
         cipherSuite = GetTlsCipherSuite()
         'Returns DicomTlsEncryptionMethodType
         Console.WriteLine("Encryption Algorithm is : {0}", GetTlsEncryptionAlgorithm(cipherSuite))
         'Returns DicomTlsAuthenticationMethodType
         Console.WriteLine("Authentication Algorithm is : {0}", GetTlsAuthenticationAlgorithm(cipherSuite))
         'Returns DicomTlsMacMethodType
         Console.WriteLine("Integrity Algorithm is : {0}", GetTlsIntegrityAlgorithm(cipherSuite))
         'Returns DicomTlsExchangeMethodType
         Console.WriteLine("Key Exchange Algorithm is : {0}", GetTlsKeyExchangeAlgorithm(cipherSuite))
         Console.WriteLine("Encryption Key Length is : {0}", GetTlsEncryptionKeyLength(cipherSuite))
         Console.WriteLine("Mutual Authentication Key Length is : {0}", GetTlsMutualAuthenticationKeyLength(cipherSuite))

      End Sub

      Public Function Wait() As Boolean
         Dim ret As WaitReturn

         ret = Utils.WaitForComplete((5 * 60) * 1000, waitEvent)

         Return (ret = WaitReturn.Complete)
      End Function

      Protected Overrides Sub OnConnect(ByVal [error] As DicomExceptionCode)
         waitEvent.Set()
      End Sub

      Protected Overrides Function OnPrivateKeyPassword(ByVal encryption As Boolean) As String
         Return "test"
      End Function

      Protected Overrides Sub OnSecureLinkReady(ByVal [error] As DicomExceptionCode)
         waitEvent.Set()
      End Sub
   End Class

   '
   ' Secure server (TLS)
   '
   Private Class ServerConnection : Inherits DicomNet

      Private serverPEM As String = Path.Combine(LEAD_VARS.ImagesDir, "server.pem")

      Public Sub New()
         MyBase.New(Nothing, DicomNetSecurityeMode.Tls)
         SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWith3DesEdeCbcSha)
         SetTlsClientCertificate(serverPEM, DicomTlsCertificateType.Pem, Nothing)
      End Sub

      Protected Overrides Function OnPrivateKeyPassword(ByVal encryption As Boolean) As String
         Return "test"
      End Function
   End Class

     Private Class Server : Inherits DicomNet
         Private client As ServerConnection

         Public Sub New()
             MyBase.New(Nothing, DicomNetSecurityeMode.None)
         End Sub

         Protected Overrides Sub OnAccept(ByVal [error] As DicomExceptionCode)
             client = New ServerConnection()

             Accept(client)
         End Sub

         Protected Overloads Overrides Sub Dispose(ByVal __p1 As Boolean)
             client.Dispose()
             MyBase.Dispose(__p1)
         End Sub
     End Class



     Public Sub TLSSecuritySample()
         DicomEngine.Startup()
         DicomNet.Startup()

         Using server As Server = New Server()
             Using client As Client = New Client()
                 server.Listen("127.0.0.1", 104, 1) ' start server
                 client.Connect(Nothing, 1000, "127.0.0.1", 104) ' connect to server
                 If (Not client.Wait()) Then ' wait for connection to finish
                     Debug.Fail("Connection timed out")
                 End If

                 Debug.Assert(client.IsConnected(), "Client not connected")

                 '
                 ' Wait for authenication
                 '
                 If (Not client.Wait()) Then
                     Debug.Fail("Connection timed out waiting for authenication")
                 End If

                 ' Once two computers have negotiated the ciphersuite, and have 
                 ' authenticated each other, they can begin transferring 
                 ' messages and data between them.

                 ' Continue with normal dicom communication

                 client.CloseForced(True)
             End Using
             server.CloseForced(True)
         End Using

         DicomEngine.Shutdown()
         DicomNet.Shutdown()
     End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class