Digital Signatures and Their Verification

In this chapter, we will learn about digital signatures and how to sign content and verify the signature later. Digital signatures have many important practical applications, such as signing documents, certificates, software, and network requests and responses, including financial transactions. Digital signatures are also important for the security of cryptocurrencies, such as Bitcoin and others. Digital signature algorithms are a necessary building block for client and server identity verification in secure network protocols, such as TLS, SSH, and IPsec. Digital signatures are used both in the TLS protocol handshake and for signing X.509 certificates, which are used for identity presentation and verification in TLS. More information about X.509 certificates will be provided in Chapter 8, X.509 Certificates and PKI. The TLS protocol will be covered in Part 4, TLS Connections and Secure Communication. Digital signatures are also used in secure...