Xojo Plugin Requires Chilkat v11.7.0+

Encrypt a PDF for a Certificate Instead of a Password

See more PDF Protection Examples

Demonstrates certificate security, where a PDF is encrypted for one or more recipients and each opens it with their own certificate and private key. No password is involved. Only the public certificate of a recipient is needed to encrypt. Each recipient has its own permissions, and the changeSecurity permission gives a recipient owner rights. PreLoadCheck tells an application that a file is certificate-encrypted and which certificates can open it. A PDF that cannot be opened, because no matching certificate and private key were provided, fails to load. Xojo Plugin

Dim success As Boolean
success = False

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

//  The PDF used in this example is available at two_page_memo.pdf

//  The recipient's certificate.  Only the public certificate is needed to encrypt.
Dim recipient As New Chilkat.Cert
success = recipient.LoadFromFile("qa_data/certs/recipient.cer")
If (success = False) Then
    System.DebugLog(recipient.LastErrorText)
    Return
End If

Dim pdf As New Chilkat.Pdf
success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf")
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

//  Call AddEncryptCert once for each recipient.
success = pdf.AddEncryptCert(recipient)
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

//  recipientPermissions[0] belongs to the first certificate added.  changeSecurity gives that
//  recipient owner rights, so the file can be managed later.
Dim json As New Chilkat.JsonObject
success = json.UpdateString("method","certificate")
success = json.UpdateBool("recipientPermissions[0].changeSecurity",True)

Dim jsonOut As New Chilkat.JsonObject
success = pdf.Protection("encrypt",json,jsonOut)
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

System.DebugLog("method: " + jsonOut.StringOf("pending.method"))
System.DebugLog("algorithm: " + jsonOut.StringOf("pending.algorithm"))
System.DebugLog("recipients: " + Str(jsonOut.SizeOfArray("pending.recipients")))

success = pdf.WriteFile("qa_output/memo_for_recipient.pdf")
If (success = False) Then
    System.DebugLog(pdf.LastErrorText)
    Return
End If

//  PreLoadCheck says how the file is protected, without loading it.
Dim reader As New Chilkat.Pdf
Dim info As New Chilkat.JsonObject
success = reader.PreLoadCheck("qa_output/memo_for_recipient.pdf",info)
If (success = False) Then
    System.DebugLog(reader.LastErrorText)
    Return
End If

System.DebugLog("saved file, method: " + info.StringOf("method"))
System.DebugLog("saved file, recipients: " + Str(info.SizeOfArray("recipients")))

//  The recipient opens it with the certificate and its private key, here from a .pfx file.
//  (On Windows, a certificate that is installed in the Windows certificate store with its private
//  key is found automatically when the PDF is loaded, and SetDecryptCert is not needed for it.)
Dim myCert As New Chilkat.Cert
success = myCert.LoadPfxFile("qa_data/pfx/recipient.pfx","pfx-password")
If (success = False) Then
    System.DebugLog(myCert.LastErrorText)
    Return
End If

success = reader.SetDecryptCert(myCert)
If (success = False) Then
    System.DebugLog(reader.LastErrorText)
    Return
End If

success = reader.LoadFile("qa_output/memo_for_recipient.pdf")
If (success = False) Then
    System.DebugLog(reader.LastErrorText)
    Return
End If

Dim empty As New Chilkat.JsonObject
Dim loadedInfo As New Chilkat.JsonObject
success = reader.Protection("getInfo",empty,loadedInfo)
If (success = False) Then
    System.DebugLog(reader.LastErrorText)
    Return
End If

System.DebugLog("opened with: " + loadedInfo.StringOf("loaded.openedWith"))
System.DebugLog("pages: " + Str(reader.NumPages))

//  Sample output:

//  method: certificate
//  algorithm: aes-256
//  recipients: 1
//  saved file, method: certificate
//  saved file, recipients: 1
//  opened with: certificate
//  pages: 2