L_DicomVerifySignature

#include "ltdic.h"

L_UINT16 EXT_FUNCTION L_DicomVerifySignature(hDS, pSignatureItem, uReserved)

HDICOMDS hDS;	/* a DICOM handle */
pDICOMELEMENT pSignatureItem;	/* pointer to a Digital Signatures Sequence Item */
L_UINT16 uReserved;	/* reserved */

Verifies Digital Signatures in the Data Set.

Parameter

Description

hDS	A DICOM handle.
pSignatureItem	Pointer to a DICOMELEMENT structure that specifies the Digital Signatures Sequence Item which corresponds to the Digital Signature to be verified. To verify all the Digital Signatures in the entire Data Set, set this parameter to NULL.
uReserved	Reserved for future use. This must be set to 0.

Returns

DICOM_SUCCESS	The Digital Signature(s) was/were verified successfully.
DICOM_ERROR_INVALID_SIGNATURE	The Digital Signature is invalid or at least one of the Digital Signatures is invalid.
(Otherwise)	An error occurred. Refer to Return Codes.

Comments

To verify all the Digital Signatures in the entire Data Set, set the pSignatureItem parameter to NULL. If at least one of these Digital Signatures is invalid, the function returns DICOM_ERROR_INVALID_SIGNATURE and does not examine the remaining Digital Signatures, if there are any.

Required DLLs and Libraries

LTDIC

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application

See Also

Functions:	L_DicomGetSignature, L_DicomFindSignature, L_DicomDeleteSignature, L_DicomCreateSignature
Topics:	Working with Digital Signatures

Example

L_VOID ExamineSignature(HDICOMDS hDS, pDICOMELEMENT pSignatureItem)
{
   L_CHAR szMsg[1024] = "";
   // The Digital Signature UID
   L_CHAR* pszSignatureUID;
   // The Digital Signature DateTime
   pVALUEDATETIME pSignatureDateTime;
   // The MAC Calculation Transfer Syntax UID
   L_CHAR* pszMacTransferSyntax;
   // The MAC Algorithm
   L_CHAR* pszMacAlgorithm;

   // Verify the Digital Signature; if pSignatureItem is NULL, the function
   // will verify all the Digital Signatures that exist in the Data Set
   L_UINT16 uRet = L_DicomVerifySignature(hDS,pSignatureItem,0);
   switch (uRet)
   {
   case DICOM_SUCCESS:
      if (pSignatureItem)
      {
         MessageBox(NULL,
                     "The Digital Signature was verified.",
                     "Sample",
                     MB_OK);
      }
      else
      {
         MessageBox(NULL,
                      "All Digital Signatures were verified "
                      "(if there are any).",
                      "Sample",
                      MB_OK);
         return;
      }
      break;

   case DICOM_ERROR_INVALID_SIGNATURE:
      if (pSignatureItem)
      {
         MessageBox(NULL,
                      "The Digital Signature is invalid.",
                      "Sample",
                      MB_OK);
      }
      else
      {
         MessageBox(NULL,
                      "At least one Digital Signature is invalid.",
                      "Sample",
                      MB_OK);
      }
      return;

   default:
      wsprintf(szMsg, "An error occurred [Error: %hu].", uRet);
      MessageBox(NULL, szMsg, "Sample", MB_OK);
      return;
   }
   pszSignatureUID = L_DicomGetSignatureUID(hDS,pSignatureItem);
   if (pszSignatureUID)
   {
      wsprintf(szMsg, "Digital Signature UID: %s\n", pszSignatureUID);
   }

   pSignatureDateTime = L_DicomGetSignatureDateTime(hDS,pSignatureItem);
   if (pSignatureDateTime)
   {
      wsprintf(szMsg, "%sDigital Signature DateTime: "
               "%02hu/%02hu/%04hu %02hu:%02hu:%02hu.%06lu %c%04li\n",
               szMsg,
               pSignatureDateTime->nMonth,
               pSignatureDateTime->nDay,
               pSignatureDateTime->nYear,
               pSignatureDateTime->nHours,
               pSignatureDateTime->nMinutes,
               pSignatureDateTime->nSeconds,
               pSignatureDateTime->nFractions,
               (pSignatureDateTime->nOffset >= 0) ? '+' : '-',
               pSignatureDateTime->nOffset);
   }

   pszMacTransferSyntax = L_DicomGetMacTransferSyntax(hDS,pSignatureItem);
   if (pszMacTransferSyntax)
   {
      wsprintf(szMsg, "%sMAC Calculation Transfer Syntax UID: %s\n",
               szMsg,
               pszMacTransferSyntax);
   }

   pszMacAlgorithm = L_DicomGetMacAlgorithm(hDS,pSignatureItem);
   if (pszMacAlgorithm)
   {
      wsprintf(szMsg, "%sMAC Algorithm: %s\n",
               szMsg,
               pszMacAlgorithm);
   }

   // The Data Elements Signed
   if (L_DicomGetSignedElementsCount(hDS,pSignatureItem) > 0)
   {
      // We will display only one
      pDICOMELEMENT pSignedElement;

      lstrcat(szMsg, "Data Elements Signed: ");
      pSignedElement = L_DicomGetSignedElement(hDS,pSignatureItem, 0);
      if (pSignedElement)
      {
         wsprintf(szMsg, "%s(%04X,%04X), ...",
                  szMsg,
                  GETGROUP(pSignedElement->nTag),
                  GETELEMENT(pSignedElement->nTag));
      }

      lstrcat(szMsg, "\n");
   }

   lstrcat(szMsg, "\nDo you want to save the Certificate of Signer?");

   // Display the information we have about the Digital Signature
   if (MessageBox(NULL, szMsg, "Sample", MB_YESNO) == IDYES)
   {
      // Save the Certificate of Signer
      L_DicomSaveCertificate(hDS,pSignatureItem, "C:\\CertOfSigner.cer",DICOM_CERTIFICATE_FORMAT_PEM);
   }
}