Ключевые слова: address, aged, archive, background, brown, business, case, classification, classified, collection, communication, concept, confidential, copy, correspondence, data, deliver, delivery, design, detective, document, envelope, forbidden, gag, government, grey, group, hide, history, important, imprint, information, intelligence, investigation, invitation, letter, letters, logistic, mail, mailing, many, memory, message, military, nobody, note, object, old, organization, paper, parchment, pile, post, postage, postal, privacy, private, receive, report, restricted, retro, safety, secrecy, secret, secure, security, send, sign, space, stack, stacked, stamp, symbol, table, text, top, view, vintage, write,