Which cipher technique rearranges the order of letters in a message?

• A. Transposition Cipher
• B. Substitution Cipher
• C. Cryptography
• D. APT

Answer: (A)

Rearranging the order of letters while keeping the same characters is characteristic of a transposition cipher. It hides the message by permuting where each letter sits, rather than changing the letter itself. For example, taking HELLO and applying a simple reversal yields OLLEH—the same letters are present, just in a different order.

In contrast, a substitution cipher would replace each letter with a different symbol or letter, so the characters themselves change rather than just their positions. Cryptography is the broader field that studies these techniques, not a specific method. APT refers to a type of cyber threat, not a cipher technique.