Ruby 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. Ruby

require 'chilkat'

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.
recipient = Chilkat::CkCert.new()
success = recipient.LoadFromFile("qa_data/certs/recipient.cer")
if (success == false)
    print recipient.lastErrorText() + "\n";
    exit
end

pdf = Chilkat::CkPdf.new()
success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

#  Call AddEncryptCert once for each recipient.
success = pdf.AddEncryptCert(recipient)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

#  recipientPermissions[0] belongs to the first certificate added.  changeSecurity gives that
#  recipient owner rights, so the file can be managed later.
json = Chilkat::CkJsonObject.new()
json.UpdateString("method","certificate")
json.UpdateBool("recipientPermissions[0].changeSecurity",true)

jsonOut = Chilkat::CkJsonObject.new()
success = pdf.Protection("encrypt",json,jsonOut)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

print "method: " + jsonOut.stringOf("pending.method") + "\n";
print "algorithm: " + jsonOut.stringOf("pending.algorithm") + "\n";
print "recipients: " + jsonOut.SizeOfArray("pending.recipients").to_s() + "\n";

success = pdf.WriteFile("qa_output/memo_for_recipient.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

#  PreLoadCheck says how the file is protected, without loading it.
reader = Chilkat::CkPdf.new()
info = Chilkat::CkJsonObject.new()
success = reader.PreLoadCheck("qa_output/memo_for_recipient.pdf",info)
if (success == false)
    print reader.lastErrorText() + "\n";
    exit
end

print "saved file, method: " + info.stringOf("method") + "\n";
print "saved file, recipients: " + info.SizeOfArray("recipients").to_s() + "\n";

#  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.)
myCert = Chilkat::CkCert.new()
success = myCert.LoadPfxFile("qa_data/pfx/recipient.pfx","pfx-password")
if (success == false)
    print myCert.lastErrorText() + "\n";
    exit
end

success = reader.SetDecryptCert(myCert)
if (success == false)
    print reader.lastErrorText() + "\n";
    exit
end

success = reader.LoadFile("qa_output/memo_for_recipient.pdf")
if (success == false)
    print reader.lastErrorText() + "\n";
    exit
end

empty = Chilkat::CkJsonObject.new()
loadedInfo = Chilkat::CkJsonObject.new()
success = reader.Protection("getInfo",empty,loadedInfo)
if (success == false)
    print reader.lastErrorText() + "\n";
    exit
end

print "opened with: " + loadedInfo.stringOf("loaded.openedWith") + "\n";
print "pages: " + reader.get_NumPages().to_s() + "\n";

#  Sample output:

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