Semantic security for the Vigen$$re cipher: The Vigen$$re cipher was a major advance in its day, but does not satisfy the modern definition of semantically secure encryption.

To show this, describe an adversary algorithm that always wins the semantic security game, without making any chosen$-$plaintext or chosen$-$ciphertext queries. Your algorithm should submit two equal$-$length candidate plaintexts and then determine which one was encrypted to produce the ciphertext returned by the challenger. Assume the challenger chooses a random key of length $10$ characters. Hint: your candidate plaintexts should be longer than $10$ characters.