In everyday life every person always has to deal with different documents. For most of us the word document evokes definite association. This is an official document with texts, signatures and seals. For example the passport. In reality we considerably often encounter with different kinds of documents, they play a great role in our lives.
So when we do shopping we deal with money, especially with paper money: Russian or of foreign countries. By buying cigarettes or alcohol we see excise (special) stamps on goods. For receiving or exchanging money we show our passports or another identity documents. Drivers show policemen vehicle registration certificate, coupons and other documents. And we do not talk about promissory, stocks and other securities with which every day we deal with more frequently.
Wherein usually unconsciously each of us solves the problem in his own way: to hold authentic or false documents. And for that willy-nilly one should knows how much that document corresponds to his/hers imagination of authenticity of the document, what protective signs does it have, that can prove the authenticity?