OcspClient Class

using DevExpress.Pdf;
using DevExpress.Office.DigitalSignatures;
using DevExpress.Office.Tsp;

using (var signer = new PdfDocumentSigner("Document.pdf"))
{
    IOcspClient ocspClient = new PdfOcspClient();
    ICrlClient crlClient = new CrlClient();

    ITsaClient tsaClient = new TsaClient(new Uri(@"https://freetsa.org/tsr"), PdfHashAlgorithm.SHA256);

    //Create a PKCS#7 signature:
    Pkcs7Signer pkcs7Signature = new Pkcs7Signer("Signing Documents//testcert.pfx", "123",
     HashAlgorithmType.SHA256, tsaClient, ocspClient, crlClient, PdfSignatureProfile.PAdES_BES);

    //Create a new signature field:
    var signatureFieldInfo = new PdfSignatureFieldInfo(1);
    signatureFieldInfo.Name = "SignatureField";
    signatureFieldInfo.SignatureBounds = new PdfRectangle(10, 10, 150, 150);

    //Apply a signature with a new signature:
    var signature =
    new PdfSignatureBuilder(pkcs7Signature, signatureFieldInfo);

    //Sign and save the document:
    signer.SaveDocument("SignedDocument.pdf", signature);
}

Imports DevExpress.Pdf
Imports DevExpress.Office.DigitalSignatures
Imports DevExpress.Office.Tsp

Using signer = New PdfDocumentSigner("Document.pdf")
  Dim ocspClient As IOcspClient = New OcspClient()
  Dim crlClient As ICrlClient = New CrlClient()

  Dim tsaClient As ITsaClient = New TsaClient(New Uri("https://freetsa.org/tsr"), HashAlgorithmType.SHA256)

  'Create a PKCS#7 signature:
  Dim pkcs7Signature As New Pkcs7Signer("Signing Documents//testcert.pfx", "123", HashAlgorithmType.SHA256, tsaClient, ocspClient, crlClient, PdfSignatureProfile.PAdES_BES)

  'Create a new signature field:
  Dim signatureFieldInfo = New PdfSignatureFieldInfo(1)
  signatureFieldInfo.Name = "SignatureField"
  signatureFieldInfo.SignatureBounds = New PdfRectangle(10, 10, 150, 150)

  'Apply a signature with a new signature field:
  Dim signature = New PdfSignatureBuilder(pkcs7Signature, signatureFieldInfo)

  'Sign and save the document:
  signer.SaveDocument("SignedDocument.pdf", signature)
End Using