Tcl Requires Chilkat v11.7.0+

Find Out Whether a PDF Needs a Password Before Loading It

See more PDF Protection Examples

Demonstrates PreLoadCheck, which examines a PDF file without loading it and without any password. It reports whether the file is encrypted, by which method and algorithm, whether a password is needed to open it, and what its permissions are. An application uses it to decide whether to ask for a password, or which certificate it needs, before calling LoadFile. PreLoadCheckBd does the same for a PDF held in memory. Tcl

load ./chilkat.dll

set success 0

#  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 PDF used in this example is available at encrypted_user_password.pdf

#  The PDF used in this example is available at no_copy_permission.pdf

set pdf [new_CkPdf]

set info [new_CkJsonObject]

#  A PDF that is not encrypted.  Nothing but "encrypted" is reported for it.
set success [CkPdf_PreLoadCheck $pdf "qa_data/pdf/two_page_memo.pdf" $info]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $info
    exit
}

puts "two_page_memo.pdf"
puts "  encrypted: [CkJsonObject_BoolOf $info encrypted]"

#  A PDF that needs a password to open.
set success [CkPdf_PreLoadCheck $pdf "qa_data/pdf/encrypted_user_password.pdf" $info]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $info
    exit
}

puts "encrypted_user_password.pdf"
puts "  encrypted: [CkJsonObject_BoolOf $info encrypted]"
puts "  method: [CkJsonObject_stringOf $info method]"
puts "  algorithm: [CkJsonObject_stringOf $info algorithm]"
puts "  openPasswordRequired: [CkJsonObject_BoolOf $info openPasswordRequired]"

#  A PDF that opens without a password but is restricted.  The permissions are readable without
#  any password.
set success [CkPdf_PreLoadCheck $pdf "qa_data/pdf/no_copy_permission.pdf" $info]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $info
    exit
}

puts "no_copy_permission.pdf"
puts "  encrypted: [CkJsonObject_BoolOf $info encrypted]"
puts "  openPasswordRequired: [CkJsonObject_BoolOf $info openPasswordRequired]"
puts "  may copy: [CkJsonObject_BoolOf $info permissions.copy]"

#  The typical use: ask for a password only when one is needed, then load.
set success [CkPdf_PreLoadCheck $pdf "qa_data/pdf/encrypted_user_password.pdf" $info]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $info
    exit
}

if {[CkJsonObject_BoolOf $info "openPasswordRequired"] == 1} then {
    #  An application would prompt for the password here.
    CkPdf_put_UserPassword $pdf "secret"
}

set success [CkPdf_LoadFile $pdf "qa_data/pdf/encrypted_user_password.pdf"]
if {$success == 0} then {
    puts [CkPdf_lastErrorText $pdf]
    delete_CkPdf $pdf
    delete_CkJsonObject $info
    exit
}

puts "loaded, pages: [CkPdf_get_NumPages $pdf]"

#  Sample output:

#  two_page_memo.pdf
#    encrypted: False
#  encrypted_user_password.pdf
#    encrypted: True
#    method: password
#    algorithm: rc4-128
#    openPasswordRequired: True
#  no_copy_permission.pdf
#    encrypted: True
#    openPasswordRequired: False
#    may copy: False
#  loaded, pages: 1

delete_CkPdf $pdf
delete_CkJsonObject $info