An overview of the symmetric ciphers supported by OpenSSL

In this section, we will review the symmetric encryption algorithms supported by OpenSSL, but, first, we need to introduce some concepts that will help us to understand the differences between ciphers, their properties, and their advantages and disadvantages. Symmetric ciphers are divided into two categories: block ciphers and stream ciphers.

Comparing block ciphers and stream ciphers

Block ciphers operate on blocks of data. For example, a popular Advanced Encryption Standard (AES) cipher has a block size of 128 bits, meaning that the cipher encrypts or decrypts data in 128-bit blocks. If the amount of data is larger than the block size, the data is split into blocks of the needed size needed for processing. If the plaintext length is not multiple of the block size, the last block is usually padded up to the block size according to the chosen padding type. Thus, in most block cipher operation modes, the ciphertext length...