VB.NET

PDF Signature Appearance Text Substitution Keywords

See more PDF Signatures Examples

This example demonstrates the text substitution keywords that can be used in the PDF signature's appearance text.

Note: This example requires Chilkat v9.5.0.85 or greater.

VB.NET

Dim success As Boolean = False

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim pdf As New Chilkat.Pdf

' Load a PDF to be signed.
success = pdf.LoadFile("qa_data/pdf/empty.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


' Options for signing are specified in JSON.
Dim json As New Chilkat.JsonObject

' In most cases, the signingCertificateV2 and signingTime attributes are required.
json.UpdateInt("signingCertificateV2",1)
json.UpdateInt("signingTime",1)

' Put the signature on page 1, top left
json.UpdateInt("page",1)
json.UpdateString("appearance.y","top")
json.UpdateString("appearance.x","left")

' Use a font scale of 7.0
json.UpdateString("appearance.fontScale","7.0")

' The appearance of the PDF signature can contain any number of text lines.
' Chilkat has defined a number of special keywords that can be used in any text line.
' Each keyword is replaced with the actual value.
' For example, "cert_cn" is replaced with the certificate subject's common name (CN).

' Here we are creating a signature with many lines of text, to demonstrate each
' keyword.
json.UpdateString("appearance.text[0]","Date/time in PDF format: current_dt")
json.UpdateString("appearance.text[1]","Current Local date/time: current_datetime")
json.UpdateString("appearance.text[2]","GMT Timestamp: current_timestamp_gmt")
json.UpdateString("appearance.text[3]","Local Timestamp: current_timestamp_local")
json.UpdateString("appearance.text[4]","GMT RFC822 date/time: current_rfc822_dt_gmt")
json.UpdateString("appearance.text[5]","Local RFC822 date/time: current_rfc822_dt_local")
json.UpdateString("appearance.text[6]","Cert DN (Distinguished Name): cert_dn")
json.UpdateString("appearance.text[7]","Cert Common Name: cert_cn")
json.UpdateString("appearance.text[8]","Cert Organizational ID (2.5.4.97): cert_org_id")
json.UpdateString("appearance.text[9]","Cert Email: cert_email")
json.UpdateString("appearance.text[10]","Cert Organization: cert_organization")
json.UpdateString("appearance.text[11]","Cert Organziational Unit: cert_ou")
json.UpdateString("appearance.text[12]","Cert State: cert_state")
json.UpdateString("appearance.text[13]","Cert Country: cert_country")
json.UpdateString("appearance.text[14]","Cert Locality: cert_locality")
json.UpdateString("appearance.text[15]","Cert Serial Number (hex): cert_serial_hex")
json.UpdateString("appearance.text[16]","Cert Serial Number (decimal): cert_serial_dec")
json.UpdateString("appearance.text[17]","Cert Thumbprint: cert_thumbprint")
json.UpdateString("appearance.text[18]","Cert Issuer Common Name: cert_issuer_cn")

Dim jpgData As New Chilkat.BinData
success = jpgData.LoadFile("qa_data/jpg/seal1.jpg")
If (success = False) Then
    Debug.WriteLine("Failed to load the JPG image.")
    Exit Sub
End If

success = pdf.SetSignatureJpeg(jpgData)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


' Specify that we want to display the JPG image in the center with 33% opacity.
json.UpdateString("appearance.image","custom-jpg")
json.UpdateString("appearance.imagePlacement","center")
json.UpdateString("appearance.imageOpacity","33")

' Load the signing certificate. (Use your own certificate.)
Dim cert As New Chilkat.Cert
success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","pfx_password")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' Tell the pdf object to use the certificate for signing.
success = pdf.SetSigningCert(cert)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


success = pdf.SignPdf(json,"qa_output/hello_signed.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("The PDF has been successfully cryptographically signed.")

' The appearance of the signature appears in Adobe Acrobat as shown here:

' (image:https://example-code.com/images/pdf_signature_text_replacements.jpg/endImage)