24 lines
597 B
Ruby
24 lines
597 B
Ruby
@atoz = Hash.new do |hash, key|
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str = ('A'..'Z').to_a.rotate(key).join("")
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hash[key] = (str << str.downcase)
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end
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def encrypt(key, plaintext)
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(1..25) === key or raise ArgumentError, "key not in 1..25"
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plaintext.tr(@atoz[0], @atoz[key])
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end
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def decrypt(key, ciphertext)
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(1..25) === key or raise ArgumentError, "key not in 1..25"
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ciphertext.tr(@atoz[key], @atoz[0])
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end
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original = "THEYBROKEOURCIPHEREVERYONECANREADTHIS"
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en = encrypt(3, original)
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de = decrypt(3, en)
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[original, en, de].each {|e| puts e}
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puts 'OK' if
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(1..25).all? {|k| original == decrypt(k, encrypt(k, original))}
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