Signature Error

I use DPLNewSignProcessFromFile and other functions rather than DPLSignFile,
and those functions work fine, but it worked weird with one Windows10 environment.
The resulting PDF file contains only '0' as signature, yet still no error
from DPL functions with this case.
Acrobat Reader says, of course, that the signature is invalid.
Does anybody know what's going on or see similar result? Any advice?


/Filter /Adobe.PPKLite
/SubFilter /adbe.pkcs7.detached
/Contents <0000000000000000000000000000000000000000 ....
/ByteRange [ 0 13275227 13275741 704
]
/M (D:20211118154446-05'00')

Hi Ingo, thank you for your response.

Yes, it worked on one Win-10 System, but not on the other Win-10 System.
 
PFX data is in PKCS12 format.
DPLSetSignProcessSubFilter only supports pkcs7 subfilter.

Here is the code we use.

// This function is a substitution of DPLSignFile function, as it lacks the ability to specify the hashing algorithm,
// DPLSetSignProcessSubFilter is doing the job in this function.

   int procID = DPLNewSignProcessFromFile(instanceID, inputFileName, openPassword);

   int rc = DPLSetSignProcessField(instanceID, procID, signatureFieldName);
   if (rc != DPL_SUCCESS) {
      return rc;
   }
   rc = DPLSetSignProcessInfo(instanceID, procID, reason, location , contactInfo);
   if (rc != DPL_SUCCESS) {
      return rc;
   }
   rc = DPLSetSignProcessSubFilter(instanceID, procID, 5 /*adbe_pkcs7_detached_with_sha512*/);
   if (rc != DPL_SUCCESS) {
      return rc;
   }
   rc = DPLSetSignProcessPFXFromString(instanceID, procID, pfxBuffer, pfxPassword);
   if (rc != DPL_SUCCESS) {
      return rc;
   }
   DPLEndSignProcessToFile(instanceID, procID, outputFileName);
   rc = DPLGetSignProcessResult(instanceID, procID);
   if (rc != DPL_SUCCESS) {
      return rc;
   }
   return rc;