Which encryption method uses a fixed substitution of letters with no repeating patterns, producing ciphertext?

Which encryption method uses a fixed substitution of letters with no repeating patterns, producing ciphertext?

• A. Caesar Cipher
• B. Cipher
• C. Encryption
• D. Random Substitution Cipher

Answer: (D)

The thing being tested is how letters get mapped to hide patterns. A random substitution cipher uses a one-to-one mapping where each plaintext letter is replaced by a randomly chosen ciphertext letter, and that mapping stays fixed for the message. Because the replacement isn’t tied to a simple rule like shifting the alphabet, the resulting ciphertext doesn’t show the regular, repeating patterns you’d get from a fixed shift. The Caesar cipher, by contrast, applies a constant shift to every letter, which creates predictable patterns that can be spotted. The other terms are too broad to describe this specific idea of a non-patterned, random-like substitution.

The thing being tested is how letters get mapped to hide patterns. A random substitution cipher uses a one-to-one mapping where each plaintext letter is replaced by a randomly chosen ciphertext letter, and that mapping stays fixed for the message. Because the replacement isn’t tied to a simple rule like shifting the alphabet, the resulting ciphertext doesn’t show the regular, repeating patterns you’d get from a fixed shift. The Caesar cipher, by contrast, applies a constant shift to every letter, which creates predictable patterns that can be spotted. The other terms are too broad to describe this specific idea of a non-patterned, random-like substitution.