plaintext recovery from key reuse

gistfile1.txt

#!/usr/bin/ruby

MESSAGES = [
"315c4eeaa8b5f8aaf9174145bf43e1784b8fa00dc71d885a804e5ee9fa40b16349c146fb778cdf2d3aff021dfff5b403b510d0d0455468aeb98622b137dae857553ccd8883a7bc37520e06e515d22c954eba5025b8cc57ee59418ce7dc6bc41556bdb36bbca3e8774301fbcaa3b83b220809560987815f65286764703de0f3d524400a19b159610b11ef3e",
"234c02ecbbfbafa3ed18510abd11fa724fcda2018a1a8342cf064bbde548b12b07df44ba7191d9606ef4081ffde5ad46a5069d9f7f543bedb9c861bf29c7e205132eda9382b0bc2c5c4b45f919cf3a9f1cb74151f6d551f4480c82b2cb24cc5b028aa76eb7b4ab24171ab3cdadb8356f",
"32510ba9a7b2bba9b8005d43a304b5714cc0bb0c8a34884dd91304b8ad40b62b07df44ba6e9d8a2368e51d04e0e7b207b70b9b8261112bacb6c866a232dfe257527dc29398f5f3251a0d47e503c66e935de81230b59b7afb5f41afa8d661cb",
"32510ba9aab2a8a4fd06414fb517b5605cc0aa0dc91a8908c2064ba8ad5ea06a029056f47a8ad3306ef5021eafe1ac01a81197847a5c68a1b78769a37bc8f4575432c198ccb4ef63590256e305cd3a9544ee4160ead45aef520489e7da7d835402bca670bda8eb775200b8dabbba246b130f040d8ec6447e2c767f3d30ed81ea2e4c1404e1315a1010e7229be6636aaa",
"3f561ba9adb4b6ebec54424ba317b564418fac0dd35f8c08d31a1fe9e24fe56808c213f17c81d9607cee021dafe1e001b21ade877a5e68bea88d61b93ac5ee0d562e8e9582f5ef375f0a4ae20ed86e935de81230b59b73fb4302cd95d770c65b40aaa065f2a5e33a5a0bb5dcaba43722130f042f8ec85b7c2070",
"32510bfbacfbb9befd54415da243e1695ecabd58c519cd4bd2061bbde24eb76a19d84aba34d8de287be84d07e7e9a30ee714979c7e1123a8bd9822a33ecaf512472e8e8f8db3f9635c1949e640c621854eba0d79eccf52ff111284b4cc61d11902aebc66f2b2e436434eacc0aba938220b084800c2ca4e693522643573b2c4ce35050b0cf774201f0fe52ac9f26d71b6cf61a711cc229f77ace7aa88a2f19983122b11be87a59c355d25f8e4",
"32510bfbacfbb9befd54415da243e1695ecabd58c519cd4bd90f1fa6ea5ba47b01c909ba7696cf606ef40c04afe1ac0aa8148dd066592ded9f8774b529c7ea125d298e8883f5e9305f4b44f915cb2bd05af51373fd9b4af511039fa2d96f83414aaaf261bda2e97b170fb5cce2a53e675c154c0d9681596934777e2275b381ce2e40582afe67650b13e72287ff2270abcf73bb028932836fbdecfecee0a3b894473c1bbeb6b4913a536ce4f9b13f1efff71ea313c8661dd9a4ce",
"315c4eeaa8b5f8bffd11155ea506b56041c6a00c8a08854dd21a4bbde54ce56801d943ba708b8a3574f40c00fff9e00fa1439fd0654327a3bfc860b92f89ee04132ecb9298f5fd2d5e4b45e40ecc3b9d59e9417df7c95bba410e9aa2ca24c5474da2f276baa3ac325918b2daada43d6712150441c2e04f6565517f317da9d3",
"271946f9bbb2aeadec111841a81abc300ecaa01bd8069d5cc91005e9fe4aad6e04d513e96d99de2569bc5e50eeeca709b50a8a987f4264edb6896fb537d0a716132ddc938fb0f836480e06ed0fcd6e9759f40462f9cf57f4564186a2c1778f1543efa270bda5e933421cbe88a4a52222190f471e9bd15f652b653b7071aec59a2705081ffe72651d08f822c9ed6d76e48b63ab15d0208573a7eef027",
"466d06ece998b7a2fb1d464fed2ced7641ddaa3cc31c9941cf110abbf409ed39598005b3399ccfafb61d0315fca0a314be138a9f32503bedac8067f03adbf3575c3b8edc9ba7f537530541ab0f9f3cd04ff50d66f1d559ba520e89a2cb2a83",
"32510ba9babebbbefd001547a810e67149caee11d945cd7fc81a05e9f85aac650e9052ba6a8cd8257bf14d13e6f0a803b54fde9e77472dbff89d71b57bddef121336cb85ccb8f3315f4b52e301d16e9f52f904"
]
target_message = "32510ba9babebbbefd001547a810e67149caee11d945cd7fc81a05e9f85aac650e9052ba6a8cd8257bf14d13e6f0a803b54fde9e77472dbff89d71b57bddef121336cb85ccb8f3315f4b52e301d16e9f52f904"

# for every hex character of first array, convert to ascii, find next array hex
# character at same index, convert to ascii, xor both ascii values, save in
# array, flatten array into space 

def xor_list( string1, string2 )
  arr1 = string1.scan /../
  arr2 = string2.scan /../  
  
  if arr1.length > arr2.length
    arr2.zip(arr1)
  else
    arr1.zip(arr2)
  end
end

def xor_ascii_chars( list1, list2 )
  message = []
  if list1.length > list2.length
    list2.each_index do |i|
      message << (list1[i] ^ list2[i])
    end
  else
    list1.each_index do |i|
      message << (list1[i] ^ list2[i])
    end
  end
  message
end

ciphertext = target_message.scan /../
ciphertext = ciphertext.map do |i|
  i.hex
end

SPACE = []
DECRYPT = []

MESSAGES.each_index do |i|
  list = xor_list MESSAGES[i], target_message
  xor_arr = list.map do |i|
    i[0].hex ^ i[1].hex
  end
  SPACE << xor_arr
end

DECRYPT = SPACE.map do |i|
  xor_ascii_chars i, ciphertext
end
puts "found space of #{SPACE.flatten.length} characters encoded in ascii"
#
# Prove that a ^ b = A ^ B
#cipher_b = MESSAGES[1].scan(/../).map do |i|
#  i.hex
#end
#puts cipher_a_xor_cipher_b.to_s
#puts cipher_b.to_s
#message_a = xor_ascii_chars( cipher_a_xor_cipher_b, cipher_b )
#puts message_a.to_s
#

# Letter frequency array
# http://en.wikipedia.org/wiki/Letter_frequency
letters = ["e", "t", "a", "o", "i", "n", "s", "h", "r"]
count = Hash.new(0)
SPACE.flatten.each do |i|
  count[i] += 1
end

decrypt_pair = []
count.each do |k,v|
  decrypt_pair << [k,v]
end

puts "XOR target message and cipher messages"
SPACE.each do |i|
  i = i.map do |character|
    character = character.chr
    if character[/[[:alnum:]]+/]
      character
    else
      "?"
    end
  end
  puts i.to_s
end

puts "XOR SPACE and target message"
DECRYPT.each do |i|
  i = i.map do |character|
    character = character.chr
    if character[/[[:alnum:]]+/]
      character
    else
      "?"
    end
  end
  puts i.to_s
end
#puts "tHE[C,E,R,P]SECUETTME"