Digital Signature Add Integrity check , Get total number of revisions and export pdf version per each signature.
i need a way to check document integrity also function to get total number of revisions that should be equal to total number of signatures in pdf file .... also the ability to export the pdf version as a pdf file per signature.
Thank you for your patience,
We've made improvements to the solution based on what you needed. Now, you can see document revision details, the entire document cover information, and check its integrity all together. Plus, the document won't lose its integrity if comments are allowed for the signature. We've also added support to ensure the document's integrity while validating the signature. Please try the workaround solution below to achieve the same outcome.
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static void Main(string[] args) { PdfLoadedDocument loadedDocument = new PdfLoadedDocument(@"Test.pdf"); PdfRevision[] revisions = loadedDocument.Revisions; Dictionary<string, int> fieldSignatures; int totalRevisions = GetSignatureTotalRevision(loadedDocument.Form.Fields, loadedDocument, out fieldSignatures); for (int i = 0; i < loadedDocument.Form.Fields.Count; i++) { PdfLoadedSignatureField pdfLoadedSignatureField = loadedDocument.Form.Fields[i] as PdfLoadedSignatureField; if (pdfLoadedSignatureField != null) { bool isCoverWholeDocument = (revisions.Length == pdfLoadedSignatureField.Revision) ? true : false; Console.WriteLine("Signature covers whole document: " + isCoverWholeDocument.ToString()); Console.WriteLine("Signature Field Name: " + pdfLoadedSignatureField.Name); Console.WriteLine("Document Revision: " + fieldSignatures[pdfLoadedSignatureField.Name] + " of " + totalRevisions); Console.WriteLine("Integrity check OK? "+ pdfLoadedSignatureField.ValidateSignature().IsSignatureValid); } } } private static int GetSignatureTotalRevision(PdfLoadedFormFieldCollection fields, PdfLoadedDocument loadedDocument, out Dictionary<string, int> fieldSignatures) { fieldSignatures = new Dictionary<string, int>(); int totalRevisions = 0; Dictionary<int, PdfLoadedSignatureField> keyValuePairs = new Dictionary<int, PdfLoadedSignatureField>(); foreach (PdfLoadedSignatureField signatureField in fields) { if (signatureField.Signature != null && signatureField.IsSigned) { totalRevisions++; keyValuePairs[signatureField.Revision] = signatureField; } } int maxRevision = 0; if (keyValuePairs.Count > 0) { int[] sort = keyValuePairs.Keys.ToArray(); System.Array.Sort(sort);
maxRevision = sort[sort.Length - 1];
Dictionary<string, int> valuePairs = new Dictionary<string, int>(); int count = 1; foreach (int revision in sort) { PdfLoadedSignatureField pdfLoadedSignatureField = keyValuePairs[revision]; valuePairs[pdfLoadedSignatureField.Name] = count++; } fieldSignatures = valuePairs; } PdfRevision[] revisions = loadedDocument.Revisions;
if(fieldSignatures.Count > 0) { if(revisions.Length > maxRevision) { totalRevisions += 1; } }
return totalRevisions; } |
Thanks for the updated code .... but can you elaborate what does the property PdfRevision.StartPosition refers to ?
what is the use of it in the above code
in this link it is referred to the starting position of the revision within the PDF document.
while PdfLoadedSignatureField.Revision is not described here
and why you are depending on PdfRevision.StartPosition since it is not unique as pdf revisions use the
concept of incremental updates ?
https://www.adobe.com/devnet-docs/acrobatetk/tools/DigSig/Acrobat_DigitalSignatures_in_PDF.pdf
Also i think syncfusion PdfLoadedDocument.Revisions calculation should be direct.
for example if pdf with no signatures it should be equal zero
if pdf with no signatures and has any number of annotations ... it should stay also zero
once a signature is added , the revisions should be 1
Any annotation is added after signature it should become two and should stays equal 2 regardless of their count but the signature does not cover the whole document till a second signature is added and then it stays equal 2 but the signature covers the whole document .
Any further annotations added regardless of their count the revisions should become three till the third signature is added and then it should stays equal three but the signature covers the whole document and so on.
Can this be the default behaviour in syncfusion ?
