Which encryption method combines rotating key values with a character mapping to enhance security?

The Vigenère cipher is an encryption method that enhances security by combining rotating key values with a character mapping. This method employs a keyword that dictates how each letter in the plaintext should be shifted. Each letter of the plaintext is shifted according to the corresponding letter of the keyword, which rotates as the encryption progresses. This rotation adds complexity since the same letter in the plaintext can be encrypted differently depending on its position in the overall message and the repeating keyword.

This technique creates a more sophisticated layer of encryption compared to simple substitution ciphers. While a substitution cipher replaces letters of the alphabet uniformly, the Vigenère cipher uses a key to determine the shift for each individual letter, significantly bolstering its resistance to frequency analysis and making it more secure against cryptographic attacks.

The other methods listed lack this combination of features. For instance, a substitution cipher uses a fixed mapping for letters, and public key infrastructure primarily relies on asymmetric cryptography for key distribution and management. Stream ciphers encrypt data one bit or byte at a time using a key stream, but they do not utilize the same type of character mapping and rotational key value mechanism as the Vigenère cipher. Therefore, the unique approach of combining rotation with character mapping makes the Vigenère cipher clearly