Message Digests
In this chapter, we will learn about message digests, also known as cryptographic hashes. Message digests, which are produced by cryptographic hash functions, have many important applications, such as data integrity checking, password verification, digital signatures, secure network protocols such as TLS, and even blockchains. We will provide an overview of the cryptographic hash functions supported by OpenSSL and recommendations on which hash functions to use and which to avoid. Then, in the practical part of this chapter, we will learn how to calculate a message digest using the command line and C code. After reading this chapter and trying the practical part, you will know why message digests are needed and how to calculate them.
We are going to cover the following topics in this chapter:
- What are message digests and cryptographic hash functions?
- Why are message digests needed?
- Assessing the security of cryptographic hash functions
- Overview...
