some small fixes

CTFs/2014-CSAW-CTF/cryptography/crypto-200/psifer-school.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python
+
+
+__author__ = "bt3gl"
+
+
+import sys
+from telnetlib import Telnet
+from caesarCipher import decipher, decipher_simple
+from pygenere import VigCrack
+
+
+
+def solve1(msg):
+  # Caesar Cipher
+  # Solve the first cypher and encode back to unicode:
+  # the method encode() returns an encoded version of the string
+  # Both method work fine.
+  # One is by freq. analysis or the other by rotating
+  dec_msg = decipher(msg)
+  #dec_msg = decipher_simple(msg)
+  dec_msg = dec_msg.split()[-1]
+  return dec_msg
+
+
+
+
+def solve2(msg):
+  # Shift cypher, but dealing with special characters
+  for j in range(2, len(msg)):
+    dec_msg = ['0'] * len(msg)
+    idec_msg,shift = 0, 0
+    for i in range(len(msg)):
+      dec_msg[idec_msg] = msg[i]
+      idec_msg += j
+      if idec_msg >= len(msg):
+        shift += 1
+        idec_msg = shift
+    dec_msg = "".join(dec_msg)
+    if "you" not in dec_msg: continue
+    return dec_msg
+
+
+
+
+
+def solve3(msg):
+  # Vigenere Cypher
+  key =  VigCrack(msg).crack_codeword()
+  dec_msg = VigCrack(msg).crack_message()
+  dec_msg =  dec_msg.replace(" ", "")
+  return key, dec_msg
+
+
+
+
+
+if __name__ == '__main__':
+
+  PORT = 12345
+  HOST = '54.209.5.48'
+  tn = Telnet(HOST ,PORT)
+
+
+  '''
+    SOLVING STAGE 1 - CEASAR CIPHER
+  '''
+
+  tn.read_until(b'psifer text: ')
+  msg_in1 = tn.read_until(b'\n').dec_msg().strip()
+
+  answer1 = solve1(msg_in1)
+
+  tn.write(answer1.encode() + b'\n')
+
+  print 'Message stage 1: ' + msg_in1
+  print
+  print 'Answer stage 1: ' + answer1
+  print
+  print
+
+
+
+  '''
+    SOLVING STAGE 2 - SPECIAL CHARS
+  '''
+  msg_in2 = tn.read_all().dec_msg()
+  msg_in2 = (msg_in2.split(':')[1]).split("Time")[0]
+
+  answer2 = solve2(msg_in2)
+
+  tn.write(answer2.encode() + b'\n')
+
+  print 'Message stage 2: ' + msg_in2
+  print
+  print 'Answer stage 2: ' + answer2
+  print
+  print
+
+
+  '''
+    SOLVING STAGE 3 - VINEGERE
+  '''
+  msg_in3 = tn.read_all().dec_msg()
+  msg_in3 = (msg_in3.split(':')[1]).split("Time")[0]
+
+
+  key, answer3 = solve3(msg_in3)
+  tn.write(answer3.encode() + b'\n')
+
+  print 'Message stage 3: ' + msg_in3
+  print
+  print 'Answer stage 3: ' + answer3
+  print '(key: ' + key + ')'