Blockchain for Real World Applications

8 Encryption and Cybersecurity

8.1 Cryptography

Cryptography is the technique of secure communication that allows only the actual sender of the message and the intended recipient to see the relevant content. The word is derived from the Greek root – kryptos (hidden).

Claude E. Shannon, who worked for years at Bell Labs, propounding the mathematical theory of cryptography, is considered as the father of cryptography. In this technique, an encrypted message replaces the character with another character. To decode encrypted content, you’ll need a grid or table that defines how letters are coded or decoded.

8.1.1 Different Types of Cryptography

In general, there are three types of cryptography:

8.1.1.1 Symmetric Key Cryptography

Symmetric cryptography is an encryption system where the sender and receiver of a message encrypt and decrypt messages using common keys. Symmetric key systems are fast and simple but require the sender and receiver to exchange keys in a secure way. In symmetric cryptography, a secret key (or private key) is a short piece or code from which messages are decrypted and encrypted. The most popular symmetric key cryptography system is the Data Encryption System (DES).

8.1.1.2 Asymmetric Key Cryptography

Asymmetric encryption is also called public key encryption, but it actually results from the simultaneous use of two mathematically coupled keys, one the public key, and the other the private key. In this process, a message is encrypted and decrypted by ...