МИНОБРНАУКИ РОССИИ

Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования

«РОССИЙСКИЙ ГОСУДАРСТВЕННЫЙ ГУМАНИТАРНЫЙ УНИВЕРСИТЕТ»

(РГГУ)

ИНСТИТУТ ИНФОРМАЦИОННЫХ НАУК И ТЕХНОЛОГИЙ БЕЗОПАСНОСТИ

ФАКУЛЬТЕТ ЗАЩИТЫ ИНФОРМАЦИИ

History of Cryptography

Реферат по дисциплине История Защиты Информации в Зарубежных Странах студента 2-го курса очной формы обучения

Поликушина Кирилла Алексеевича

Руководитель кандидат исторических наук, доцент Русецкая Ирина Алексеевна

Contents

Glossary……………………………………………………………….3

Introduction…………………………………………………………... 4

Part 1. Ancient Times – Classical cryptography ……………………..5

Part 2. Al-Kindi – Frequency Analysis……………………………….6

Part 3. The Rise of the West – The Era of the Black Chambers…...…7

Part 4. Room 40 – Zimmermann Telegram…………………………...9

Part 5. Enigma – Way of Mechanization …………………………….11

Part 6. RSA – Public-key Cryptography……………………………..12

Conclusion………………………………………………………..…..13

Glossary

Cryptography (from Greek κρυπτός – hidden and γράφω – writing) is a science about cipher, steganography and other way of hiding a message or its meaning. It’s also include cryptanalysis.

Ciphering is an algorithm, that helps to protect message from reading. Generally cipher use key to change open information to hiden.

Coding, as opposed to the cipher, change type of information. For example, Morse code convert symbols to dot’n’dash code, that can easily can be convert to sound.

Key is a secret number or keyword, etc. that use in algorithm to cipher open text of massage and decipher ciphered text.

Dechipher is a algorithm, that use a known key to ciphered text for getting open text. It’s not a try to break a cipher.

Steganography is a science of hiding text. But it isn’t connect text’s meaning; steganography hides the existence of message.

Cryptanalysis is a part of cryptography contrasted to ciphering. Cryptanalysis teaches how to break cipher.

Frequency analysis is an analysis of counting number of frequency meeting letters in a text.

Introduction

And it may well be doubted whether human ingenuity can construct an enigma of the kind which human ingenuity may not, by proper application, resolve.

- Edgar Allan Poe.¹

At the beginning of XX century cryptography has reborn and took its place in the world. In the world of informational technologies people wants to keep their secret and secure important information from contestants. That’s why cryptography so important today. Nowadays it’s a new young science, and it’s far away from classic cryptography: computer technology brought new abilities and set new targets. Ciphers took the first place. But experience of past help to invent new non-standard ways of evolving. Today the good old ideas are still relevant. Also the classic non-computer cryptography continues to evolve.

It’s start a long time ago, when writing began to emerge. People encrypt important government correspondence and diplomatic information, prescriptions and even magic formula. At the same time there were people who want to get confidentiality information. So, together with cryptography was evolve cryptanalysis. Without cryptanalysis, cryptography wouldn’t improve. That’s why evolve of cryptography should always be considered together with evolve of cryptoanalysis

Part 1. Ancient Times – Classical cryptography

When the world was younger by a few thousand years, ciphers already were very popular way to protect a message. Caesar cipher was the simplest and easiest cipher to use. Its algorithm is a alphabetical shift. Caesar changed letter A to letter B, B to C, etc. Width of the shift could be switched and was the key to the cipher. Such cipher named as monoalphabetic replacement cipher.

In fact, there were a lot of different ciphers, codes, math algorithms and tricks, that was very helpful in ciphering. It’ll take a long time to list all of them, so I want to show most interesting and popular tricks. The first trick is a space between words. You should never let it stay, or your cipher would cipher would be very weak. The second trick some more difficult. Ancient Phoenicians, whose alphabet became the prototype for most people, have no vowels in the alphabet. It made studying much shorter, but reading — harder. Same trick has been used in XIV century to make frequency analysis more difficult. Cryptographer-linguist John Ronald Reuel Tolkien in his philological works offers changes vowels to dots over previous consonant. Although much of the work of Professor refers to linguistic cryptography, they will be discussed later, because these works were written in the 20th century

Except ciphers, steganography evolve as well. Special attention pointed at invisible ink. Many ink recipes survived to nowadays. Invisible ink appear after thermal effects, light effect, reagents effect etc.

Another steganography method was Aeneas’ book code. Aeneas recommend to make little needle’s poined in a book.² It is very simple, but effective device.

There are much more tricks, methods. Cryptographers have a huge collections of them, so much information about classical cryptography, but progress does not stand still, and we are not.