Question

Which cipher is the One-Time Pad based off of?

a) Playfair cipher
b) Caesar cipher
c) Vigenère cipher
d) Vernam cipher

Answer 1

The One-Time Pad is based on the Vernam cipher, which is known for its use of a random key stream to achieve secure encryption and is considered unbreakable when used correctly.

Step-by-step explanation:

The One-Time Pad is based off the Vernam cipher. The Vernam cipher, developed by Gilbert Vernam, is a symmetric-key cipher where each character of the plaintext is combined with a character from a random key stream. To achieve maximum security, the key stream must be truly random, as long as the message itself, and used only once. Hence, the name One-Time Pad. Other ciphers like the Playfair cipher, Caesar cipher, and Vigenère cipher, have fixed systems for encryption and decryption, making them vulnerable to different levels of cryptanalysis. In comparison, the One-Time Pad is considered unbreakable when used correctly, because it produces random output that cannot be reliably decrypted without the specific key used to encrypt it.