Solve rotr for hidden string

test_rotr.rb

#!/usr/bin/env ruby

# Solved from https://docs.google.com/forms/d/1h6LtvCS3tVosk1-dbEsX54DsLxE6Xg9tTWUT2C-JqMk/viewform

hidden_string = 'bddpvout ejggfsfou gps qbttxpse b sfvtf opu Ep'

def rotr_word(word, number)
  letters = word.split('')
              .map do |letter|
                (letter.ord + number).chr
              end
  letters.join('')
end

def rotr(string, number)
  words = string.split(' ')
  result_words = words.map do |word|
    rotr_word(word, number)
  end
  result_words.join(' ')
end

256.times do |number|
  puts rotr(hidden_string, -number)
end