Classic ASP
PDF Signature with Background Image (Seal/Stamp/etc.)

Demonstrates how to sign a PDF with an appearance that includes a background image, such as a seal, stamp, etc.
Note: This example requires Chilkat v9.5.0.85 or greater.
Chilkat Classic ASP Downloads

Classic ASP
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

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

set pdf = Server.CreateObject("Chilkat.Pdf")

'  Load a PDF to be signed.
'  The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
success = pdf.LoadFile("qa_data/pdf/hello.pdf")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pdf.LastErrorText) & "</pre>"
    Response.End
End If

'  Options for signing are specified in JSON.
set json = Server.CreateObject("Chilkat.JsonObject")

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

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

'  Use a font scale of 10.0
success = json.UpdateString("appearance.fontScale","10.0")

'  In this example, the appearance of the digital signature will contain three lines:
'  1) The signing certificate's common name
'  2) The current date/time
'  3) Some arbitrary text.
'  The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
'  The keyword "current_dt" is replaced with the current date/time.
'  Any number of appearance text lines can be added.
success = json.UpdateString("appearance.text[0]","Digitally signed by: cert_cn")
success = json.UpdateString("appearance.text[1]","current_dt")
success = json.UpdateString("appearance.text[2]","The crazy brown fox jumps over the lazy dog.")

'  Load a JPG image to be shown with 30% opacity in the background.
'  (the image must be in the JPG format)
'  The sample university.jpb is available at https://example-code.com/images/university.jpg

set jpgData = Server.CreateObject("Chilkat.BinData")
success = jpgData.LoadFile("qa_data/jpg/university.jpg")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( "Failed to load the JPG image.") & "</pre>"
    Response.End
End If

success = pdf.SetSignatureJpeg(jpgData)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pdf.LastErrorText) & "</pre>"
    Response.End
End If

'  Specify that we want to display the JPG image in the center with 30% opacity.
success = json.UpdateString("appearance.image","custom-jpg")
success = json.UpdateString("appearance.imagePlacement","center")
success = json.UpdateString("appearance.imageOpacity","30")

'  Load the signing certificate. (Use your own certificate.)
set cert = Server.CreateObject("Chilkat.Cert")
success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( cert.LastErrorText) & "</pre>"
    Response.End
End If

'  Tell the pdf object to use the certificate for signing.
success = pdf.SetSigningCert(cert)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pdf.LastErrorText) & "</pre>"
    Response.End
End If

success = pdf.SignPdf(json,"qa_output/hello_signed.pdf")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( pdf.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "The PDF has been successfully cryptographically signed.") & "</pre>"

'  The appearance of the signature appears in Adobe Acrobat as shown below.
'  The JPG is automatically scaled to the size of the signature based on the signature's font scale
'  and number of text lines.
'  (image:https://example-code.com/images/signature2.jpg/endImage)

%>
</body>
</html>