Certified Ethical Hacker (CEH) Practice Exam 2026 – Your All-in-One Guide to Exam Success!

A block cipher is best described as a cipher that operates on larger groups of bits, typically referred to as blocks. In block ciphers, data is divided into fixed-size blocks (often 64 or 128 bits), and each block is encrypted independently using a symmetric key. This enables the block cipher to enhance security and efficiency in data encryption by processing chunks of data rather than individual bits or bytes.

Unlike stream ciphers, which encrypt data one bit at a time and are optimal for real-time applications, block ciphers offer strong encryption algorithms that can be used for files and other data types where data must be secured in larger segments. Furthermore, block ciphers can also incorporate various modes of operation (such as CBC, ECB, and CTR) to secure data effectively while also allowing for the potential handling of various data patterns.

Understanding this characteristic is essential for recognizing the distinct operation modes of different ciphers, as well as their respective applications in cybersecurity practices.