lib/crapto/examples/repeating_key_xor_solve.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 module repeating_key_xor_solve is example
  16
  17 import base64
  18 import crapto
  19
  20 # Check usage
  21 if args.length != 1 then
  22         print "Usage: repeating_key_xor_solve <cipher_file>"
  23         exit 1
  24 end
  25
  26 # Read the cipher from the file
  27 var cipher_bytes = args[0].to_path.read_all_bytes.decode_base64
  28
  29 # Create a RepeatingKeyXorCipher object to manipulate your ciphertext
  30 var xorcipher = new RepeatingKeyXorCipher
  31 xorcipher.ciphertext = cipher_bytes
  32
  33 # Try to find the best candidate key
  34 xorcipher.find_key
  35
  36 # Decrypt the cipher according to the found key
  37 xorcipher.decrypt
  38
  39 # Check the resulting plaintext out...
  40 print xorcipher.plaintext