Western Governors University (WGU) ITAS2140 D431 Digital Forensics in Cybersecurity Practice Exam

The cipher that is described as a simple single-alphabet substitution that rotates characters is ROT13. This encryption technique encodes letters by shifting them 13 places in the alphabet. For example, the letter 'A' becomes 'N', 'B' becomes 'O', and so on. Since the alphabet has 26 letters, applying ROT13 a second time returns the original text, making it a symmetric cipher.

In contrast, the other options represent different types of ciphers. The Vigenère cipher uses a keyword to determine the amount of shift for each letter, thus providing a more complex encryption as compared to a straightforward rotation. The Atbash cipher is a specific substitution cipher that replaces each letter with its mirror in the alphabet (A ↔ Z, B ↔ Y, etc.), rather than rotating positions. The Scytale is an ancient cryptographic tool that involves wrapping a strip of paper around a cylinder to encrypt messages, differing significantly from the concept of rotating characters in a single alphabet.

Thus, the definition of a cipher that involves simply rotating characters aligns perfectly with the mechanics of ROT13.