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chinnumuniyappanchinnumuniyappan
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Merge pull request #199 from SyncfusionExamples/259676
259676: Added more information about the time stamp in the UG documentation link
2 parents 2db63d8 + 07c33f6 commit f9b62d2

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  • Digital Signature/Validate-the-digitally-signed-PDF-signature/.NET/Validate-the-digitally-signed-PDF-signature

1 file changed

+132
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‎Digital Signature/Validate-the-digitally-signed-PDF-signature/.NET/Validate-the-digitally-signed-PDF-signature/Program.cs‎

Lines changed: 132 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -4,60 +4,135 @@
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using Syncfusion.Pdf.Security;
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using System.Security.Cryptography.X509Certificates;
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//Get the stream from the document.
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FileStream documentStream = new FileStream(Path.GetFullPath(@"Data/Input.pdf"), FileMode.Open, FileAccess.Read);
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//Load an existing signed PDF document.
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PdfLoadedDocument loadedDocument = new PdfLoadedDocument(documentStream);
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//Get signature field.
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PdfLoadedSignatureField signatureField = loadedDocument.Form.Fields[0] as PdfLoadedSignatureField;
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//X509Certificate2Collection to check the signer's identity using root certificates.
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X509CertificateCollection collection = new X509CertificateCollection();
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//Creates a certificate instance from PFX file with private key.
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FileStream certificateStream = new FileStream(Path.GetFullPath(@"Data/PDF.pfx"), FileMode.Open, FileAccess.Read);
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byte[] data = new byte[certificateStream.Length];
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certificateStream.Read(data, 0, data.Length);
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//Create new X509Certificate2 with the root certificate.
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X509Certificate2 certificate = new X509Certificate2(data, "syncfusion");
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//Add the certificate to the collection.
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collection.Add(certificate);
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//Validate signature and get the validation result.
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PdfSignatureValidationResult result = signatureField.ValidateSignature(collection);
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//Checks whether the signature is valid or not.
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SignatureStatus status = result.SignatureStatus;
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//Checks whether the document is modified or not.
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bool isModified = result.IsDocumentModified;
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Console.WriteLine("Document modified: " + isModified);
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//Signature details.
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string issuerName = signatureField.Signature.Certificate.IssuerName;
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DateTime validFrom = signatureField.Signature.Certificate.ValidFrom;
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DateTime validTo = signatureField.Signature.Certificate.ValidTo;
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string signatureAlgorithm = result.SignatureAlgorithm;
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DigestAlgorithm digestAlgorithm = result.DigestAlgorithm;
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Console.WriteLine("Issuer Name: " + issuerName);
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Console.WriteLine("Valid From: " + validFrom);
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Console.WriteLine("Valid To: " + validTo);
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Console.WriteLine("Signature Algorithm: " + signatureAlgorithm);
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Console.WriteLine("Digest Algorithm: " + digestAlgorithm);
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//Revocation validation details.
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RevocationResult revocationDetails = result.RevocationResult;
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RevocationStatus revocationStatus = revocationDetails.OcspRevocationStatus;
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bool isRevokedCRL = revocationDetails.IsRevokedCRL;
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Console.WriteLine("Revocation Status: " + revocationStatus);
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Console.WriteLine("Is Revoked CRL: " + isRevokedCRL);
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//Close the document.
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loadedDocument.Close(true);
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// Load the input PDF document stream from the specified file path
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using (FileStream documentStream = new FileStream(Path.GetFullPath(@"Data/Input.pdf"), FileMode.Open, FileAccess.Read))
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{
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// Load the signed PDF document using the stream
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using (PdfLoadedDocument loadedDocument = new PdfLoadedDocument(documentStream))
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{
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// Retrieve the first signature field from the PDF form
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PdfLoadedSignatureField signatureField = loadedDocument.Form.Fields[0] as PdfLoadedSignatureField;
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// Create a certificate collection to hold trusted root certificates for validation
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X509CertificateCollection collection = new X509CertificateCollection();
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// Load the root certificate from a PFX file (includes private key)
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FileStream certificateStream = new FileStream(Path.GetFullPath(@"Data/PDF.pfx"), FileMode.Open, FileAccess.Read);
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byte[] data = new byte[certificateStream.Length];
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certificateStream.Read(data, 0, data.Length);
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// Create an X509Certificate2 instance using the loaded certificate data and password
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X509Certificate2 certificate = new X509Certificate2(data, "syncfusion");
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// Add the certificate to the validation collection
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collection.Add(certificate);
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// Validate the signature using the provided certificate collection
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PdfSignatureValidationResult result = signatureField.ValidateSignature(collection);
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// Initialize flag to detect timestamp signatures
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bool isTimeStampSignature = false;
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// Check if the TimeStampInformation object is not null
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if (result.TimeStampInformation != null)
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{
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// Check if the signature is a document timestamp
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if (result.TimeStampInformation.IsDocumentTimeStamp)
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{
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isTimeStampSignature = true;
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Console.WriteLine("Signature is a document timestamp signature.");
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}
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// Retrieve signer certificates if available
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PdfSignerCertificate[] certificates = result.TimeStampInformation.SignerCertificates;
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if (certificates != null && certificates.Length > 0)
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{
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Console.WriteLine($"Retrieved {certificates.Length} signer certificate(s).");
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}
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else
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{
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Console.WriteLine("No signer certificates found.");
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}
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// Retrieve the main certificate
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X509Certificate2 certificate2 = result.TimeStampInformation.Certificate;
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if (certificate2 != null)
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{
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Console.WriteLine($"Certificate Subject: {certificate2.Subject}");
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}
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else
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{
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Console.WriteLine("No certificate found.");
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}
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// Retrieve timestamp date
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DateTime dateTime = result.TimeStampInformation.Time;
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Console.WriteLine($"Timestamp Date: {dateTime}");
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// Retrieve timestamp policy ID
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string policyID = result.TimeStampInformation.TimeStampPolicyId;
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if (!string.IsNullOrEmpty(policyID))
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{
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Console.WriteLine($"Timestamp Policy ID: {policyID}");
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}
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else
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{
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Console.WriteLine("No Timestamp Policy ID found.");
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}
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// Check if the timestamp is valid
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bool valid = result.TimeStampInformation.IsValid;
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Console.WriteLine($"Timestamp Validity: {(valid ? "Valid" : "Invalid")}");
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}
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else
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{
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Console.WriteLine("TimeStampInformation is null. Cannot retrieve timestamp details.");
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}
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// Check if the signature is valid
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SignatureStatus status = result.SignatureStatus;
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// Check if the document has been modified after signing
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bool isModified = result.IsDocumentModified;
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// Check if Long-Term Validation (LTV) is enabled in the signature
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bool isLtvEnabled = result.LtvVerificationInfo.IsLtvEnabled;
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// Check if Certificate Revocation List (CRL) data is embedded in the PDF
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bool isCrlEmbedded = result.LtvVerificationInfo.IsCrlEmbedded;
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// Check if Online Certificate Status Protocol (OCSP) data is embedded in the PDF
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bool isOcspEmbedded = result.LtvVerificationInfo.IsOcspEmbedded;
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// Output the validation results to the console
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Console.WriteLine("Document modified: " + isModified);
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Console.WriteLine("LTV enabled: " + isLtvEnabled);
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Console.WriteLine("CRL embedded: " + isCrlEmbedded);
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Console.WriteLine("OCSP embedded: " + isOcspEmbedded);
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// Extract and display signature certificate details
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string issuerName = signatureField.Signature.Certificate.IssuerName;
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DateTime validFrom = signatureField.Signature.Certificate.ValidFrom;
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DateTime validTo = signatureField.Signature.Certificate.ValidTo;
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string signatureAlgorithm = result.SignatureAlgorithm;
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DigestAlgorithm digestAlgorithm = result.DigestAlgorithm;
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Console.WriteLine("Issuer Name: " + issuerName);
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Console.WriteLine("Valid From: " + validFrom);
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Console.WriteLine("Valid To: " + validTo);
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Console.WriteLine("Signature Algorithm: " + signatureAlgorithm);
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Console.WriteLine("Digest Algorithm: " + digestAlgorithm);
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// Extract and display revocation validation details
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RevocationResult revocationDetails = result.RevocationResult;
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RevocationStatus revocationStatus = revocationDetails.OcspRevocationStatus;
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bool isRevokedCRL = revocationDetails.IsRevokedCRL;
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Console.WriteLine("Revocation Status: " + revocationStatus);
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Console.WriteLine("Is Revoked CRL: " + isRevokedCRL);
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// Close the loaded PDF document and release resources
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loadedDocument.Close(true);
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}
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}

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