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259676: Added more information about the time stamp in the UG documentation link #199

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merged 2 commits into from
Sep 19, 2025
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259676: Added more information about the time stamp in the UG documentation link #199

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259676: Added more information about the time stamp in the UG docume…
sameerkhan001 Sep 17, 2025
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259676: Resolved the given feedback
sameerkhan001 Sep 18, 2025
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189 changes: 132 additions & 57 deletions ...igitally-signed-PDF-signature/.NET/Validate-the-digitally-signed-PDF-signature/Program.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,60 +4,135 @@
using Syncfusion.Pdf.Security;
using System.Security.Cryptography.X509Certificates;

//Get the stream from the document.
FileStream documentStream = new FileStream(Path.GetFullPath(@"Data/Input.pdf"), FileMode.Open, FileAccess.Read);

//Load an existing signed PDF document.
PdfLoadedDocument loadedDocument = new PdfLoadedDocument(documentStream);

//Get signature field.
PdfLoadedSignatureField signatureField = loadedDocument.Form.Fields[0] as PdfLoadedSignatureField;

//X509Certificate2Collection to check the signer's identity using root certificates.
X509CertificateCollection collection = new X509CertificateCollection();

//Creates a certificate instance from PFX file with private key.
FileStream certificateStream = new FileStream(Path.GetFullPath(@"Data/PDF.pfx"), FileMode.Open, FileAccess.Read);
byte[] data = new byte[certificateStream.Length];
certificateStream.Read(data, 0, data.Length);

//Create new X509Certificate2 with the root certificate.
X509Certificate2 certificate = new X509Certificate2(data, "syncfusion");

//Add the certificate to the collection.
collection.Add(certificate);

//Validate signature and get the validation result.
PdfSignatureValidationResult result = signatureField.ValidateSignature(collection);

//Checks whether the signature is valid or not.
SignatureStatus status = result.SignatureStatus;

//Checks whether the document is modified or not.
bool isModified = result.IsDocumentModified;

Console.WriteLine("Document modified: " + isModified);

//Signature details.
string issuerName = signatureField.Signature.Certificate.IssuerName;
DateTime validFrom = signatureField.Signature.Certificate.ValidFrom;
DateTime validTo = signatureField.Signature.Certificate.ValidTo;
string signatureAlgorithm = result.SignatureAlgorithm;
DigestAlgorithm digestAlgorithm = result.DigestAlgorithm;

Console.WriteLine("Issuer Name: " + issuerName);
Console.WriteLine("Valid From: " + validFrom);
Console.WriteLine("Valid To: " + validTo);
Console.WriteLine("Signature Algorithm: " + signatureAlgorithm);
Console.WriteLine("Digest Algorithm: " + digestAlgorithm);

//Revocation validation details.
RevocationResult revocationDetails = result.RevocationResult;
RevocationStatus revocationStatus = revocationDetails.OcspRevocationStatus;
bool isRevokedCRL = revocationDetails.IsRevokedCRL;

Console.WriteLine("Revocation Status: " + revocationStatus);
Console.WriteLine("Is Revoked CRL: " + isRevokedCRL);

//Close the document.
loadedDocument.Close(true);
// Load the input PDF document stream from the specified file path
using (FileStream documentStream = new FileStream(Path.GetFullPath(@"Data/Input.pdf"), FileMode.Open, FileAccess.Read))
{

// Load the signed PDF document using the stream
using (PdfLoadedDocument loadedDocument = new PdfLoadedDocument(documentStream))
{

// Retrieve the first signature field from the PDF form
PdfLoadedSignatureField signatureField = loadedDocument.Form.Fields[0] as PdfLoadedSignatureField;

// Create a certificate collection to hold trusted root certificates for validation
X509CertificateCollection collection = new X509CertificateCollection();

// Load the root certificate from a PFX file (includes private key)
FileStream certificateStream = new FileStream(Path.GetFullPath(@"Data/PDF.pfx"), FileMode.Open, FileAccess.Read);
byte[] data = new byte[certificateStream.Length];
certificateStream.Read(data, 0, data.Length);

// Create an X509Certificate2 instance using the loaded certificate data and password
X509Certificate2 certificate = new X509Certificate2(data, "syncfusion");

// Add the certificate to the validation collection
collection.Add(certificate);

// Validate the signature using the provided certificate collection
PdfSignatureValidationResult result = signatureField.ValidateSignature(collection);

// Initialize flag to detect timestamp signatures
bool isTimeStampSignature = false;

// Check if the TimeStampInformation object is not null
if (result.TimeStampInformation != null)
{
// Check if the signature is a document timestamp
if (result.TimeStampInformation.IsDocumentTimeStamp)
{
isTimeStampSignature = true;
Console.WriteLine("Signature is a document timestamp signature.");
}

// Retrieve signer certificates if available
PdfSignerCertificate[] certificates = result.TimeStampInformation.SignerCertificates;
if (certificates != null && certificates.Length > 0)
{
Console.WriteLine($"Retrieved {certificates.Length} signer certificate(s).");
}
else
{
Console.WriteLine("No signer certificates found.");
}

// Retrieve the main certificate
X509Certificate2 certificate2 = result.TimeStampInformation.Certificate;
if (certificate2 != null)
{
Console.WriteLine($"Certificate Subject: {certificate2.Subject}");
}
else
{
Console.WriteLine("No certificate found.");
}

// Retrieve timestamp date
DateTime dateTime = result.TimeStampInformation.Time;
Console.WriteLine($"Timestamp Date: {dateTime}");

// Retrieve timestamp policy ID
string policyID = result.TimeStampInformation.TimeStampPolicyId;
if (!string.IsNullOrEmpty(policyID))
{
Console.WriteLine($"Timestamp Policy ID: {policyID}");
}
else
{
Console.WriteLine("No Timestamp Policy ID found.");
}

// Check if the timestamp is valid
bool valid = result.TimeStampInformation.IsValid;
Console.WriteLine($"Timestamp Validity: {(valid ? "Valid" : "Invalid")}");
}
else
{
Console.WriteLine("TimeStampInformation is null. Cannot retrieve timestamp details.");
}
// Check if the signature is valid
SignatureStatus status = result.SignatureStatus;

// Check if the document has been modified after signing
bool isModified = result.IsDocumentModified;

// Check if Long-Term Validation (LTV) is enabled in the signature
bool isLtvEnabled = result.LtvVerificationInfo.IsLtvEnabled;

// Check if Certificate Revocation List (CRL) data is embedded in the PDF
bool isCrlEmbedded = result.LtvVerificationInfo.IsCrlEmbedded;

// Check if Online Certificate Status Protocol (OCSP) data is embedded in the PDF
bool isOcspEmbedded = result.LtvVerificationInfo.IsOcspEmbedded;

// Output the validation results to the console
Console.WriteLine("Document modified: " + isModified);
Console.WriteLine("LTV enabled: " + isLtvEnabled);
Console.WriteLine("CRL embedded: " + isCrlEmbedded);
Console.WriteLine("OCSP embedded: " + isOcspEmbedded);

// Extract and display signature certificate details
string issuerName = signatureField.Signature.Certificate.IssuerName;
DateTime validFrom = signatureField.Signature.Certificate.ValidFrom;
DateTime validTo = signatureField.Signature.Certificate.ValidTo;
string signatureAlgorithm = result.SignatureAlgorithm;
DigestAlgorithm digestAlgorithm = result.DigestAlgorithm;

Console.WriteLine("Issuer Name: " + issuerName);
Console.WriteLine("Valid From: " + validFrom);
Console.WriteLine("Valid To: " + validTo);
Console.WriteLine("Signature Algorithm: " + signatureAlgorithm);
Console.WriteLine("Digest Algorithm: " + digestAlgorithm);

// Extract and display revocation validation details
RevocationResult revocationDetails = result.RevocationResult;
RevocationStatus revocationStatus = revocationDetails.OcspRevocationStatus;
bool isRevokedCRL = revocationDetails.IsRevokedCRL;

Console.WriteLine("Revocation Status: " + revocationStatus);
Console.WriteLine("Is Revoked CRL: " + isRevokedCRL);

// Close the loaded PDF document and release resources
loadedDocument.Close(true);
}
}
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