Ключевые слова: abstract, army, background, banner, blackboard, blank, board, certificate, chalk, chalkboard, classified, confidential, damaged, design, document, espionage, frame, government, grunge, hook, icon, important, imprint, information, iron, key, label, lock, lockstitch, metal, military, mission, mysterious, object, open, pad, padlock, paperwork, password, pattern, post, print, privacy, private, protection, reflection, restricted, rubber, safe, safety, seal, secrecy, secret, secure, security, shackle, shining, shiny, sign, spy, stamp, steal, steel, striped, stronghold, symbol, tag, text, texture, top, unlock, urgent, white,