Cryptography Essentials

In this chapter, we will cover the fundamental notions of cryptography necessary to fully understand the security features of blockchain and Distributed Ledger Technologies (DLTs). We'll outline the differences between symmetric and asymmetric cryptography, and we'll tell cryptography and hashing functions apart.

We will also explore some of the operations realized by the most prominent data structure implemented by blockchain, the Merkle tree, which exploits cryptography primitives to fulfill architectural core goals.

The topics we will cover in this chapter are the following:

• A glimpse into cryptography
• Symmetric versus asymmetric cryptography
• Elliptic cryptography in blockchain
• SHA hashing and digital signatures in practice
• Blockchain Merkle trees

Let's start our analysis with a glimpse into cryptography.

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