Summary

In this chapter, we have learned what symmetric encryption is and how it differs from asymmetric encryption. We also learned what a cipher is, what block ciphers and stream ciphers are, how cipher security is measured, and how much security is enough. Then, we learned which ciphers are supported by OpenSSL, which you should use in which situation, and which ciphers you should avoid. We also learned which cipher operation modes exist, how they differ, and which you should use.

We discussed padding, why it exists, and in which cases you should use it. We also covered oracle and how to download and install OpenSSL. We explored and saw what is included in the OpenSSL toolkit, how to initialize the OpenSSL library, and how to compile and link your program with the OpenSSL library. Finally, we learned how to generate an encryption key and an IV, how to encrypt and decrypt a file using the OpenSSL command-line tool, and how to encrypt and decrypt a file programmatically using the...