Chicago Ruby hack night puzzle http://www.puzzlenode.com/puzzles/12-secret-messages

vigenere_cipher.rb

class CaesarCipher
  attr_accessor :shift_value
  def initialize(shift_value)
    @shift_value = shift_value
    @shifted_alphabet_array = ("A".."Z").to_a.rotate(@shift_value)
    @alphabet_array = ("A".."Z").to_a
  end

  def cipher(text)
    text.upcase.split("").each_with_object("") do |chr, cipher_text|
      cipher_text << @shifted_alphabet_array[@alphabet_array.index(chr)]
    end
  end

  def decipher(ciphered_text)
    ciphered_text.upcase.split("").each_with_object("") do |chr, decipher_text|
      decipher_text << @alphabet_array[@shifted_alphabet_array.index(chr)]
    end
  end
end

class VigenereCipher

  def initialize(key)
    @key = random_shift_value(key)
  end

  DICTIONARY = "/usr/share/dict/words"

  def dictionary_lookup(text)
    File.readlines(DICTIONARY).select { |word| word if (word.chomp.downcase == text.downcase) }.first
  end

  def random_shift_value(text)
    [*0..25].each do |shift_value|
      caesar_cipher_instance = CaesarCipher.new(shift_value)
      deciphered_text = caesar_cipher_instance.decipher(text)
      return deciphered_text if dictionary_lookup(deciphered_text)
    end
  end

  def compacted_decipher(word)
    word = word.gsub(/\W/,"").split(" ").join("")
    keys = @key.downcase.split("").each_with_object([]) { |chr,keys_array| keys_array << ("a".."z").to_a.index(chr) }
    keys_mulitplier = (word.split("").size / keys.size) + 1
    keys = keys * keys_mulitplier
    word.downcase.split("").zip(keys).each_with_object("") do |kchar, deciphered_word|
      deciphered_word << character(ciphered_alphabet_array(kchar[1]).index(kchar[0]))
    end
  end

  def decipher(word)
    compacted_word = compacted_decipher(word)
    word.split("").each_with_index do |character, index|
      (compacted_word.insert(index, character)) if character.match(/\W/)
    end
    compacted_word.upcase
  end

  def ciphered_alphabet_array(shift_value)
    ("a".."z").to_a.rotate(shift_value)
  end

  def character(index)
    ("a".."z").to_a[index]
  end
end

vigenere_cipher = VigenereCipher.new("RLCOPY")
word = "IONDVQY DZH QNTY KLQRY BVISEK TYHME JERWLF; ZHV YEYOAEW RRBEI WEFZE FI HRGTY EYG UNTH. SS GLC WLR COEGIEY TYDX V EEK KEIK HVDVQ, OT JHIZY TF PI ZUSK VXEGNXH XUGT DHR FNOLOH SKAI; VIRONX WLNZ DVDXU, G NVFIFYAIB IAJ, WZOP PUMV ZLRT IK ZMYR CFPI."
deciphered_word = vigenere_cipher.decipher(word)

p deciphered_word