Book Image

Cryptography Algorithms

By : Massimo Bertaccini
Book Image

Cryptography Algorithms

By: Massimo Bertaccini

Overview of this book

Cryptography Algorithms is designed to help you get up and running with modern cryptography algorithms. You'll not only explore old and modern security practices but also discover practical examples of implementing them effectively. The book starts with an overview of cryptography, exploring key concepts including popular classical symmetric and asymmetric algorithms, protocol standards, and more. You'll also cover everything from building crypto codes to breaking them. In addition to this, the book will help you to understand the difference between various types of digital signatures. As you advance, you will become well-versed with the new-age cryptography algorithms and protocols such as public and private key cryptography, zero-knowledge protocols, elliptic curves, quantum cryptography, and homomorphic encryption. Finally, you'll be able to apply the knowledge you've gained with the help of practical examples and use cases. By the end of this cryptography book, you will be well-versed with modern cryptography and be able to effectively apply it to security applications.
Table of Contents (15 chapters)
1
Section 1: A Brief History and Outline of Cryptography
3
Section 2: Classical Cryptography (Symmetric and Asymmetric Encryption)
7
Section 3: New Cryptography Algorithms and Protocols
12
Section 4: Homomorphic Encryption and the Crypto Search Engine

Chapter 4: Introducing Hash Functions and Digital Signatures

Since time immemorial, most contracts, meaning any kind of agreement between people or groups, have been written on paper and signed manually using a particular signature at the end of the document to authenticate the signatory. This was possible because, physically, the signatories were in the same place at the moment of signing. The signatories could usually trust each other because a third trustable person (a notary or legal entity) guaranteed their identities as a super-party entity.

Nowadays, people wanting to sign contracts often don't know each other and frequently share documents to be signed via email, signing them without a trustable third party to guarantee their identities.

Imagine that you are signing a contract with a third party and will be sending it via the internet. Now, consider the third party as untrustable, and you don't want to expose the document's contents to an unknown person...