class PDF::Reader::StandardSecurityHandler

def pad_pass(p="")

pp61 of spec
Pads supplied password to 32bytes using PassPadBytes as specified on 
def pad_pass(p="")
  if p.nil? || p.empty?
    PassPadBytes.pack('C*')
  else
    p[(0...32)] + PassPadBytes[0...(32-p.length)].pack('C*')
  end
end