Which cipher rearranges characters without using substitution?

• A. Substitution Cipher
• B. Caesar Cipher
• C. Transposition Cipher
• D. Polyalphabetic Cipher

Answer: (C)

Rearranging the order of characters without changing which characters appear is what a transposition cipher does. It applies a fixed permutation to the positions of the plaintext letters, so the ciphertext contains the same letters as the plaintext, just in a different order. There is no substitution of letters to other symbols. In contrast, a Caesar cipher is a substitution that shifts every letter by a fixed amount, changing the characters themselves. A polyalphabetic cipher also substitutes letters, using multiple alphabets, rather than merely permuting their positions. So the method that rearranges without substitution is the transposition cipher.