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GetTlsEncryptionKeyLength Method
See Also 
Leadtools.Dicom Namespace > DicomNet Class : GetTlsEncryptionKeyLength Method



cipher
The cipher suite for which to get the length of the encryption key.
cipher
The cipher suite for which to get the length of the encryption key.
Returns the effective length, in bits, of the encryption key associated with the specified cipher suite (56 for DES, etc.).

Syntax

Visual Basic (Declaration) 
Public Function GetTlsEncryptionKeyLength( _
   ByVal cipher As DicomTlsCipherSuiteType _
) As Integer
Visual Basic (Usage)Copy Code
Dim instance As DicomNet
Dim cipher As DicomTlsCipherSuiteType
Dim value As Integer
 
value = instance.GetTlsEncryptionKeyLength(cipher)
C# 
public int GetTlsEncryptionKeyLength( 
   DicomTlsCipherSuiteType cipher
)
C++/CLI 
public:
int GetTlsEncryptionKeyLength( 
   DicomTlsCipherSuiteType cipher
) 

Parameters

cipher
The cipher suite for which to get the length of the encryption key.

Return Value

The effective length of the encryption key associated with the specified cipher suite.

Example

This is a comprehensive sample that shows how to use DICOM Secure communication using TLS.

Visual BasicCopy Code
<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 = LeadtoolsExamples.Common.ImagesPath.Path + "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 = LeadtoolsExamples.Common.ImagesPath.Path + "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
C#Copy Code
[StructLayout(LayoutKind.Sequential)]
public struct MSG
{
    public IntPtr hwnd;
    public uint message;
    public IntPtr wParam;
    public IntPtr lParam;
    public uint time;
    public System.Drawing.Point p;
}
public enum WaitReturn
{
    Complete,
    Timeout,
}

class Utils
{
    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    static extern bool PeekMessage(out MSG lpMsg, IntPtr hWnd,
                                   uint wMsgFilterMin, uint wMsgFilterMax,
                                   uint wRemoveMsg);

    [DllImport("user32.dll")]
    static extern bool TranslateMessage([In] ref MSG lpMsg);
    [DllImport("user32.dll")]
    static extern IntPtr DispatchMessage([In] ref MSG lpmsg);

    const uint PM_REMOVE = 1;

    public static WaitReturn WaitForComplete(double mill, WaitHandle wh)
    {
        TimeSpan goal = new TimeSpan(DateTime.Now.AddMilliseconds(mill).Ticks);

        do
        {
            MSG msg = new MSG();

            if (PeekMessage(out msg, IntPtr.Zero, 0, 0, PM_REMOVE))
            {
                TranslateMessage(ref msg);
                DispatchMessage(ref msg);
            }

            if (wh.WaitOne(new TimeSpan(0, 0, 0), false))
            {
                return WaitReturn.Complete;
            }

            if (goal.CompareTo(new TimeSpan(DateTime.Now.Ticks)) < 0)
            {
                return WaitReturn.Timeout;
            }

        } while (true);
    }
}

//
// Secure client (TLS)
//
class Client : DicomNet
{
    AutoResetEvent waitEvent = new AutoResetEvent(false);
    string clientPEM = LeadtoolsExamples.Common.ImagesPath.Path + "client.pem";

    public Client()
        : base(null, DicomNetSecurityeMode.Tls)
    {
       SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWithDesCbcSha);
       SetTlsClientCertificate(clientPEM,DicomTlsCertificateType.Pem, null);

       //Over here we can get detailed information about the Cipher Suite
       DicomTlsCipherSuiteType cipherSuite = GetTlsCipherSuite();// Can also call GetTlsCipherSuiteByIndex
       //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));
    }

    public bool Wait()
    {
        WaitReturn ret;

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

        return (ret == WaitReturn.Complete);
    }

    protected override void OnConnect(DicomExceptionCode error)
    {
        waitEvent.Set();
    }

    protected override string OnPrivateKeyPassword(bool encryption)
    {
        return "test";
    }

    protected override void OnSecureLinkReady(DicomExceptionCode error)
    {
        waitEvent.Set();
    }
}

//
// Secure server (TLS)
//
class ServerConnection : DicomNet
{

    string serverPEM = LeadtoolsExamples.Common.ImagesPath.Path + "server.pem";

    public ServerConnection()
        : base(null, DicomNetSecurityeMode.Tls)
    {
       SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWith3DesEdeCbcSha);
       SetTlsClientCertificate(serverPEM, DicomTlsCertificateType.Pem, null);
    }

    protected override string OnPrivateKeyPassword(bool encryption)
    {
        return "test";
    }
}

class Server : DicomNet
{
    ServerConnection client;

    public Server()
        : base(null, DicomNetSecurityeMode.None)
    {
    }

    protected override void OnAccept(DicomExceptionCode error)
    {
        client = new ServerConnection();

        Accept(client);
    }

    protected override void Dispose(bool __p1)
    {
        client.Dispose();
        base.Dispose(__p1);
    }
}


public void TLSSecuritySample()
{
    DicomEngine.Startup();
    DicomNet.Startup();

    using (Server server = new Server())
    {
        using (Client client = new Client())
        {
            server.Listen("127.0.0.1", 104, 1); // start server
            client.Connect(null, 1000, "127.0.0.1", 104); // connect to server
            if (!client.Wait()) // wait for connection to finish
            {
                Debug.Fail("Connection timed out");
            }

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

            //
            // Wait for authenication
            //
            if (!client.Wait())
            {
                Debug.Fail("Connection timed out waiting for authenication");
            }

            // 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);
        }
        server.CloseForced(true);
    }

    DicomEngine.Shutdown();
    DicomNet.Shutdown();
}
SilverlightCSharpCopy Code
SilverlightVBCopy Code

Remarks

There are differences between the size of the key and the effective length. The security of a key is given by the effective length, not by the size (a DES key has 8 bytes, just like a DES40 key, but the first has 56 bits effective, and the second only 40).

Requirements

Target Platforms: Silverlight 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)

See Also

Leadtools.Dicom requires a Medical toolkit server license and unlock key. For more information, refer to: Imaging Pro/Document/Medical Features