GetSignedElementsCount Method

Summary

Returns the number of Data Elements covered by the specified Digital Signature.

Syntax

C++/CLI

public int GetSignedElementsCount( 
   DicomElement signatureItem 
)

public: 
int GetSignedElementsCount(  
   DicomElement^ signatureItem 
)

Parameters

signatureItem
The Digital Signatures Sequence Item that corresponds to the Digital Signature. This cannot be null.

Return Value

The number of Data Elements covered by the specified Digital Signature.

Remarks

The Digital Signatures Sequence Item of a Digital Signature should reference an item under the Message Authentication Code (MAC) Parameters Sequence associated with the Digital Signatures Sequence. The Data Elements Signed (0400,0020) under the referenced MAC Parameters Sequence Item specifies the signed Data Elements. Call this method to obtain the number of Data Elements specified by this Data Element. Along with this method, call the GetSignedElement method to enumerate the Data Elements covered by the Digital Signature.

The following methods can also be used to get information about the Digital Signature:

Example

using Leadtools; 
using Leadtools.Dicom; 
 
 
public void ExamineSignature(DicomDataSet dataset, DicomElement signatureItem) 
{ 
   // Verify the Digital Signature; if pSignatureItem is NULL, the function 
   // will verify all the Digital Signatures that exist in the Data Set 
   bool ret = dataset.VerifySignature(signatureItem); 
   if (ret == true) 
   { 
      if (signatureItem != null) 
      { 
         Console.WriteLine("Sample: The Digital Signature was verified."); 
 
      } 
      else 
      { 
         Console.WriteLine("Sample: All Digital Signatures were verified (if there are any)."); 
      } 
   } 
   else 
   { 
      if (signatureItem != null) 
      { 
         Console.WriteLine("Sample: The Digital Signature is invalid."); 
      } 
      else 
      { 
         Console.WriteLine("Sample: At least one Digital Signature is invalid."); 
      } 
   } 
   // The Digital Signature UID 
   StringBuilder msg = new StringBuilder(); 
   msg.Append(dataset.GetSignatureUID(signatureItem)); 
 
   // The Digital Signature DateTime 
   DicomDateTimeValue digitalSignatureDateTime = dataset.GetSignatureDateTime(signatureItem); 
   if (digitalSignatureDateTime.IsEmpty == false) 
   { 
      msg.AppendFormat(" Digital Signature DateTime:{0}/{1}/{2} {3}:{4}:{5}.{6} {7}{8}{9}", 
         digitalSignatureDateTime.Month, 
         digitalSignatureDateTime.Day, 
         digitalSignatureDateTime.Year, 
         digitalSignatureDateTime.Hours, 
         digitalSignatureDateTime.Minutes, 
         digitalSignatureDateTime.Seconds, 
         digitalSignatureDateTime.Fractions, 
         (digitalSignatureDateTime.Offset >= 0) ? '+' : '-', 
         digitalSignatureDateTime.Offset, 
         Environment.NewLine); 
   } 
   string macTransferSyntax = dataset.GetMacTransferSyntax(signatureItem); 
   if (macTransferSyntax != null) 
   { 
      msg.AppendFormat("MAC Calculation Transfer Syntax UID: {0}", macTransferSyntax); 
   } 
 
   string macAlgorithm = dataset.GetMacAlgorithm(signatureItem); 
   if (macAlgorithm != null) 
   { 
      msg.AppendFormat("MAC Algorithm: {0}", macAlgorithm); 
   } 
   // The Data Elements Signed 
   if (dataset.GetSignedElementsCount(signatureItem) > 0) 
   { 
      // We will display only one 
      DicomElement element = dataset.GetSignedElement(signatureItem, 0); 
      msg.AppendFormat(" Data Elements Signed:{0}{1}{1}", element.Tag, Environment.NewLine); 
   } 
   msg.AppendFormat("{0}Do you want to save the Certificate of Signer?", Environment.NewLine); 
 
   Console.WriteLine($"Sample: {msg.ToString()}"); 
   dataset.SaveCertificate(signatureItem, Path.Combine(LEAD_VARS.ImagesDir, "CertOfSigner.cer"), DicomCertificateFormat.Pem); 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}