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Über dieses Buch

Cryptography, secret writing, is probably as old as writing itself. But only recently has it become the object of extensive scientific studies. Vast new applications to data security are one explanation for this. Perhaps a more important reason for the huge growth of scientific research on cryptography is the seminal idea of public-key cryptography and the resulting new vistas on the possibilities of communication. This book gives a broad overview of public-key cryptography, covering its essence and advantages, various public-key cryptosystems and protocols. It also gives a comprehensive introduction to classical cryptography and cryptanalysis. The book is self-contained and suitable both as a text and as a reference. It starts from the beginning but also includes some 1989 developments. The presentation is in many ways new, with some new results. The treatment is rigorous but avoids unnecessary formalism. The plaintext examples in the book form a package of basic sauna knowledge.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Classical Two-Way Cryptography

Abstract
The art and science of cryptography consists of two worlds. There is the world of legal communications: parties such as legal users of a data bank exchanging messages. This world can be viewed as open and sunlit. There is also the dark world of the enemy who illegally tries to intercept the messages and do all kinds of vicious things. For people in the legal world, it is desirable that the enemy understands very little of the messages. The enemy, on the other hand, would like to have easily understandable messages.
Arto Salomaa

Chapter 2. The Idea of Public Keys

Abstract
Think about any of the cryptosystems presented in Chapter 1, or any other similar systems. There will be no difficulties in the decryption process for a cryptanalyst who has learned the encryption method. The encryption and decryption keys coincide even in such a sophisticated system as DES. So you give away your secrets if you work with one of the systems mentioned and publicize your encryption method.
Arto Salomaa

Chapter 3. Knapsack Systems

Abstract
Public-key cryptosystems based on the knapsack problem were already briefly discussed in Example 2.1 in Chapter 2. It was also pointed out that knapsack systems are very suitable for illustrating all basic ideas behind public-key cryptography. The setup is also versatile enough to produce new variants to avoid cryptographic weaknesses.
Arto Salomaa

Chapter 4. RSA

Abstract
The most widely used and tested public-key cryptosystem was originally introduced by Rivest, Shamir and Adleman, and is now referred to as the RSA system. It is based on an amazingly simple number-theoretical (one could even say arithmetical) idea, and yet it has been able to resist all cryptanalytic attacks. The idea is a clever use of the fact that, while it is easy to multiply two large primes, it is extremely difficult to factorize their product. Thus, the product can be publicized and used as the encryption key. The primes themselves cannot be recovered from the product. On the other hand, the primes are needed for decryption. Thus, we have an excellent framework for a public-key cryptosystem. Moreover, the details can be explained very fast —that’s why we called the system “amazingly simple”.
Arto Salomaa

Chapter 5. Other Bases of Cryptosystems

Abstract
The framework presented in Section 2.2 for the construction of public-key cryptosystems is very general. Indeed, the area or subject matter of the underlying problem is not specified in any way. Any one-way street could be worth a try, and many streets have actually been tried. By now there exist numerous public-key cryptosystems, based on quite diverse concepts.
Arto Salomaa

Chapter 6. Cryptographic Protocols: Surprising Vistas for Communication

Abstract
A protocol usually refers to customs and regulations dealing with diplomatic formality, precedence and etiquette. Typically, a protocol determines a map for seating the participants, or the order of speeches. It has happened that an international conference has spent most of the time while arguing about the seating protocol.
Arto Salomaa

Backmatter

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