CompTIA Security+ (SY0-601) — Question 806

Which of the following is a cryptographic concept that operates on a fixed length of bits?

Answer options

• A. Block cipher
• B. Hashing
• C. Key stretching
• D. Salting

Correct answer: A

Explanation

The correct answer is A, Block cipher, as it encrypts data in fixed-size blocks. Hashing, while it produces a fixed-length output, does not involve encryption in the traditional sense. Key stretching refers to techniques that make weak keys stronger, and salting is a method to protect against rainbow table attacks, neither of which operate on fixed lengths of bits.