PdfDocumentSigner.VerifyLtv(PdfLtvOptions) Method

Returns Long Term Validation (LTV) records about the state of the signature certificate.

Namespace: DevExpress.Pdf

Assembly: DevExpress.Docs.v24.2.dll

NuGet Package: DevExpress.Document.Processor

Declaration

C#

public IEnumerable<PdfLtvResult> VerifyLtv(
    PdfLtvOptions options
)

VB.NET

Public Function VerifyLtv(
    options As PdfLtvOptions
) As IEnumerable(Of PdfLtvResult)

Parameters

Name	Type	Description
options	PdfLtvOptions	A PdfLtvOptions object that specifies an LTV information request.

Returns

Type	Description
IEnumerable<PdfLtvResult>	A collection of PdfLtvResult objects that contain information about LTV certificate verification.

Remarks

LTV (Long Term Validation) supplies a record of certificate state at the time it was signed. To verify a certificate, the signature must include a digital timestamp. Use the PdfPkcs7Signature.IsDocumentTimeStamp to check whether this is true. Note that certificate verification requires the OCSP or CRL responder to have its certificates online. Set PdfLtvOptions.TryFetchCrlOnline and PdfLtvOptions.TryFetchOcspOnline to true to obtain the certificate status in an OCSP/CRL response when you call the VerifyLtv method.

The following example executes an LTV check for a signature from the “Signed_file.pdf” file:

C#

using DevExpress.Office.DigitalSignatures;

namespace ConsoleApp {
    internal class Program {
        static void Main(string[] args) {
            VerifyLTV();
        }
        public static void VerifyLTV(){
            using (PdfDocumentSigner documentSigner = new PdfDocumentSigner("Signed_file.pdf")){
                PdfLtvOptions options = new PdfLtvOptions(){
                    TryFetchCrlOnline = true,
                    TryFetchOcspOnline = true,
                    VerifyEntireCertificateChain = true,
                };
                var result = documentSigner.VerifyLtv(options);
                foreach (var entry in result){
                    Console.WriteLine("Signature Name: {0}", entry.SignatureFieldName);
                    Console.WriteLine("Certificate in chain: {0}", entry.CertificateRevocationResults.Count);
                    foreach(var revocation in entry.CertificateRevocationResults){
                        Console.WriteLine("Certificate {0}", revocation.Key.Subject);
                        Console.WriteLine("Is certificate revoked?: {0}", revocation.Value.IsCrlRevoked);
                        if (revocation.Value.IsCrlRevoked)
                            Console.WriteLine("Is CRL found online?: {0}", revocation.Value.IsCrlFoundOnline);
                        Console.WriteLine("OCSP Response Status: {0}", revocation.Value.OcspRevocationStatus);
                        if (revocation.Value.OcspRevocationStatus != PdfOcspRevocationStatus.None)
                            Console.WriteLine("Is OCSP found online?: {0}", revocation.Value.IsOcspFoundOnline);
                        Console.WriteLine();
                    }
                }
            }
        }
    }
}       

VB.NET

Imports DevExpress.Pdf

Namespace ConsoleApp
    Friend Class Program
        Shared Sub Main(ByVal args() As String) 
            VerifyLTV()
        End Sub
        Public Shared Sub VerifyLTV()
            Using documentSigner As New PdfDocumentSigner("Signed_file.pdf")
                Dim options As New PdfLtvOptions() With {
                    .TryFetchCrlOnline = True,
                    .TryFetchOcspOnline = True,
                    .VerifyEntireCertificateChain = True
                }
                Dim result = documentSigner.VerifyLtv(options)
                For Each entry In result
                    Console.WriteLine("Signature Name: {0}", entry.SignatureFieldName)
                    Console.WriteLine("Certificate in chain: {0}", entry.CertificateRevocationResults.Count)
                    For Each revocation In entry.CertificateRevocationResults
                        Console.WriteLine("Certificate {0}", revocation.Key.Subject)
                        Console.WriteLine("Is certificate revoked?: {0}", revocation.Value.IsCrlRevoked)
                        If revocation.Value.IsCrlRevoked Then
                            Console.WriteLine("Is CRL found online?: {0}", revocation.Value.IsCrlFoundOnline)
                        End If
                        Console.WriteLine("OCSP Response Status: {0}", revocation.Value.OcspRevocationStatus)
                        If revocation.Value.OcspRevocationStatus <> PdfOcspRevocationStatus.None Then
                            Console.WriteLine("Is OCSP found online?: {0}", revocation.Value.IsOcspFoundOnline)
                        End If
                        Console.WriteLine()
                    Next revocation
                Next entry
            End Using
        End Sub
    End Class
End Namespace