# Single-byte XOR cipher

# The hex encoded string:

# 1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736
# ... has been XOR'd against a single character. Find the key, decrypt the message.

# You can do this by hand. But don't: write code to do it for you.

# How? Devise some method for "scoring" a piece of English plaintext. Character
# frequency is a good metric. Evaluate each output and choose the one with the best score.

