Single-byte XOR cipher

This is the third crypto challenge in set 1 from cryptopals, which is the qualifying set.

The difficulty level is relatively easy, to solve this problem I have used the programming language Go.

The input is a hex encoded string:

1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736

which has been XOR'd against a single character. Find the key, and decrypt the message.

Devise some method for "scoring" a piece of English plaintext. Character frequency is a good metric. Evaluate each output and choose …

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