DicomOpenSslContextCreationSettings Class

Summary

Provides properties to change the security options from the defaults when the security mode used by DicomNet is set to the Transport Layer Security (TLS) mode.

Syntax

Objective-C

C++/CLI

public class DicomOpenSslContextCreationSettings : IDisposable

@interface LTDicomOpenSslContextCreationSettings : NSObject

public ref class DicomOpenSslContextCreationSettings

Remarks

Use this class with Initialize to change the security options from the defaults. This toolkit uses SSL (Secure Socket Layer) and TLS (Transport Layer Security) to implement security. Developed by Netscape, the Secure Socket Layer (SSL) protocol is designed to ensure the security of data being communicated between two points over a network, and uses TCP as the communication layer. SSL provides a way for the client and server to authenticate each other, ensures the integrity of the data during a session, and ensures that the data remains private between the client and the server. The Transport Layer Security (TLS) protocol is based on the SSL protocol.

Please note that a full discussion of SSL and TLS is beyond the scope of this help.

Example

using Leadtools; 
using Leadtools.Dicom; 
 
 
[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); 
   } 
 
   public static void SetupTlsContext(DicomNet net, string certName) 
   { 
      string serverCA = Path.Combine(LEAD_VARS.ImagesDir, "ca.pem"); 
 
      if (net != null) 
      { 
         DicomOpenSslContextCreationSettings settings = new DicomOpenSslContextCreationSettings( 
            // represents DicomOpenSslContextCreationSettings.MethodType 
            DicomSslMethodType.SslV23, 
            // represents DicomOpenSslContextCreationSettings.CertificationAuthoritiesFileName 
            serverCA, 
            // represents DicomOpenSslContextCreationSettings.VerificationFlags 
            DicomOpenSslVerificationFlags.Peer | DicomOpenSslVerificationFlags.FailIfNoPeerCertificate, 
            // represents DicomOpenSslContextCreationSettings.MaximumVerificationDepth 
            2, 
            // represents DicomOpenSslContextCreationSettings.Options 
            DicomOpenSslOptionsFlags.NoSslV2 | DicomOpenSslOptionsFlags.AllBugWorkarounds 
            ); 
         net.Initialize(null, DicomNetSecurityMode.Tls, settings); 
         net.SetTlsClientCertificate(certName, DicomTlsCertificateType.Pem, null); 
      } 
   } 
} 
 
//  
// Secure client (TLS)  
//  
class Client : DicomNet 
{ 
   AutoResetEvent waitEvent = new AutoResetEvent(false); 
   string clientPEM = Path.Combine(LEAD_VARS.ImagesDir, "client.pem"); 
 
   public Client() 
      : base(null, DicomNetSecurityMode.Tls) 
   { 
      SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWithDesCbcSha); 
      Utils.SetupTlsContext(this, clientPEM); 
   } 
 
   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 = Path.Combine(LEAD_VARS.ImagesDir, "server.pem"); 
 
   public ServerConnection() 
      : base(null, DicomNetSecurityMode.Tls) 
   { 
      SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWith3DesEdeCbcSha); 
      SetTlsClientCertificate(serverPEM, DicomTlsCertificateType.Pem, null); 
   } 
 
   protected override string OnPrivateKeyPassword(bool encryption) 
   { 
      return "test"; 
   } 
 
   // The OnVerify callback gets called twice, once for each certificate in the certificate chain. 
   protected override int OnVerify(int ok, string certificateString, DicomSecurityCertificateException ex) 
   { 
      string certificateMessageString = "Received Client Certificate:\n" + certificateString; 
 
      // Log that the SCP received the Client Certificate 
      Debug.WriteLine(certificateMessageString); 
 
      if (ex.Code != DicomSecurityCertificateExceptionCode.Success) 
      { 
         string message = string.Format("Error {0}: {1}", ex.Code, ex.Message); 
 
         // Log the error with Client Certificate 
         Debug.WriteLine(message); 
      } 
      return ok; 
   } 
} 
 
class Server : DicomNet 
{ 
   string serverPEM = Path.Combine(LEAD_VARS.ImagesDir, "server.pem"); 
 
   ServerConnection client; 
 
   public Server() 
      : base(null, DicomNetSecurityMode.Tls) 
   { 
      SetTlsCipherSuiteByIndex(0, DicomTlsCipherSuiteType.DheRsaWith3DesEdeCbcSha); 
      Utils.SetupTlsContext(this, serverPEM); 
   } 
 
   protected override void OnAccept(DicomExceptionCode error) 
   { 
      client = new ServerConnection(); 
 
      Utils.SetupTlsContext(client, serverPEM); 
 
      Accept(client); 
   } 
 
   protected override string OnPrivateKeyPassword(bool encryption) 
   { 
      return "test"; 
   } 
 
   protected override void Dispose(bool __p1) 
   { 
      client.Dispose(); 
      base.Dispose(__p1); 
   } 
} 
 
public void TLSSecuritySample() 
{ 
   //Assert test to check file exists before running code 
   string clientPEM = Path.Combine(LEAD_VARS.ImagesDir, "ca.pem"); 
   Assert.IsTrue(File.Exists(clientPEM) == true, "Missing file: " + clientPEM); 
 
   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.  
 
         //Now we can get detailed information about the Cipher Suite   
         DicomTlsCipherSuiteType cipherSuite = client.GetTlsCipherSuite();// Can also call GetTlsCipherSuiteByIndex   
 
         Debug.WriteLine("Encryption Algorithm is : {0}", client.GetTlsEncryptionAlgorithm(cipherSuite)); 
         Debug.WriteLine("Authentication Algorithm is : {0}", client.GetTlsAuthenticationAlgorithm(cipherSuite)); 
         Debug.WriteLine("Integrity Algorithm is : {0}", client.GetTlsIntegrityAlgorithm(cipherSuite)); 
         Debug.WriteLine("Key Exchange Algorithm is : {0}", client.GetTlsKeyExchangeAlgorithm(cipherSuite)); 
         Debug.WriteLine("Encryption Key Length is : {0}", client.GetTlsEncryptionKeyLength(cipherSuite)); 
         Debug.WriteLine("Mutual Authentication Key Length is : {0}", client.GetTlsMutualAuthenticationKeyLength(cipherSuite)); 
 
         // Continue with normal dicom communication  
 
         client.CloseForced(true); 
      } 
      server.CloseForced(true); 
   } 
 
   DicomEngine.Shutdown(); 
   DicomNet.Shutdown(); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

Requirements

Target Platforms

Reference

DicomOpenSslContextCreationSettings Members

Leadtools.Dicom Namespace

Initialize Method

DicomNet Class

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Help Version 23.0.2024.8.20

Leadtools.Dicom Assembly

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