(Xojo Plugin) Sign a PDF (Simplest Possible Example)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF using mostly default options in the simplest way possible.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// 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.
// The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
Dim success As Boolean
success = pdf.LoadFile("qa_data/pdf/hello.pdf")
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
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.
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 the signing certificate. (Use your own certificate.)
Dim cert As New Chilkat.Cert
success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret")
If (success = False) Then
    System.DebugLog(cert.LastErrorText)
    Return
End If

// Tell the pdf object to use the certificate for signing.
success = pdf.SetSigningCert(cert)
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

success = pdf.SignPdf(json,"qa_output/hello_signed.pdf")
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

System.DebugLog("The PDF has been successfully cryptographically signed.")

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