VB.NET Requires Chilkat v11.7.0+

Restrict Printing, Copying and Editing of a PDF

See more PDF Protection Examples

Demonstrates a PDF that opens without a password but limits what a reader may do with it. The user password is left empty, the owner password protects the restrictions, and the permissions member of the JSON says what is denied. Chilkat honors these permissions itself: with copying denied, text extraction is refused unless the PDF is loaded with its owner password. An empty owner password is refused when anything is restricted, because anyone opening the file would then have owner rights. 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.

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

Dim pdf As New Chilkat.Pdf
success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


'  No user password: the PDF opens without a prompt.  The owner password is what protects the
'  restrictions, so it must not be empty when anything is restricted.
pdf.UserPassword = ""
pdf.OwnerPassword = "owner-secret"

Dim json As New Chilkat.JsonObject
json.UpdateString("permissions.print","lowQuality")
json.UpdateBool("permissions.copy",False)
json.UpdateBool("permissions.modify",False)
json.UpdateBool("permissions.annotate",False)
'  The permissions not mentioned (fillForms, assemble, accessibility) stay granted.

Dim jsonOut As New Chilkat.JsonObject
success = pdf.Protection("encrypt",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If

success = pdf.WriteFile("qa_output/memo_restricted.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


'  Anyone can open the result, with the rights of a user.
Dim reader As New Chilkat.Pdf
success = reader.LoadFile("qa_output/memo_restricted.pdf")
If (success = False) Then
    Debug.WriteLine(reader.LastErrorText)
    Exit Sub
End If

Dim empty As New Chilkat.JsonObject
Dim info As New Chilkat.JsonObject
success = reader.Protection("getInfo",empty,info)
If (success = False) Then
    Debug.WriteLine(reader.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("opened with: " & info.StringOf("loaded.openedWith"))
Debug.WriteLine("print: " & info.StringOf("loaded.permissions.print"))
Debug.WriteLine("copy: " & info.BoolOf("loaded.permissions.copy"))
Debug.WriteLine("modify: " & info.BoolOf("loaded.permissions.modify"))

'  Chilkat honors the restrictions.  Copying is not permitted, so the text cannot be extracted.
Dim opts As New Chilkat.JsonObject
Dim extractOut As New Chilkat.JsonObject
Dim sb As New Chilkat.StringBuilder
success = reader.ExtractTextSb("text",opts,sb,extractOut)
If (success = False) Then
    Debug.WriteLine("Text extraction was refused: the PDF does not permit copying.")
End If


'  The owner password lifts every restriction.
Dim owner As New Chilkat.Pdf
owner.OwnerPassword = "owner-secret"
success = owner.LoadFile("qa_output/memo_restricted.pdf")
If (success = False) Then
    Debug.WriteLine(owner.LastErrorText)
    Exit Sub
End If

Dim ownerInfo As New Chilkat.JsonObject
success = owner.Protection("getInfo",empty,ownerInfo)
If (success = False) Then
    Debug.WriteLine(owner.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("opened with: " & ownerInfo.StringOf("loaded.openedWith"))
success = owner.ExtractTextSb("text",opts,sb,extractOut)
If (success = False) Then
    Debug.WriteLine(owner.LastErrorText)
    Exit Sub
End If

Debug.WriteLine("characters extracted with the owner password: " & sb.Length)

'  Sample output:

'  opened with: emptyPassword
'  print: lowQuality
'  copy: False
'  modify: False
'  Text extraction was refused: the PDF does not permit copying.
'  opened with: owner
'  characters extracted with the owner password: 1048