picoctf 2013 - Bitwise: 55

You see the doors to the loading bay of the hangar, but they are locked. However, you are able to extract the password verification program from the control panel... Can you find the password to gain access to the loading bay?

SRC:

#!/usr/bin/env python

user_submitted = "ub3rs3cr3t"

if len(user_submitted) != 10:

  print "Wrong"

  exit()

verify_arr = [193, 35, 9, 33, 1, 9, 3, 33, 9, 225]

user_arr = []

for char in user_submitted:

  # '<<' is left bit shift

  # '>>' is right bit shift

  # '|' is bit-wise or

  # '^' is bit-wise xor

  # '&' is bit-wise and

  user_arr.append( (((ord(char) << 5) | (ord(char) >> 3)) ^ 111) & 255 )

if (user_arr == verify_arr):

  print "Success"

else:

  print "Wrong"

user_submitted = raw_input("Enter Password: ")

 Có đoạn chỉ dẫn nè:

  # '<<' is left bit shift ==> dịch trái bit

  # '>>' is right bit shift ==> dịch phải bit

  # '|' is bit-wise or ==> toán tử or

  # '^' is bit-wise xor ==> toán tử xor

  # '&' is bit-wise and ==> toán tử and

Mình sẽ dùng 1 bảng kí tự được bitwise trước để đối chiếu với mảng

verify_arr = [193, 35, 9, 33, 1, 9, 3, 33, 9, 225]

Bảng này mình mới chỉ dùng các kí tự số và các kí tự in thường "0123456789abcdefghijklmnopqrstuvwxyz"

#!/usr/bin/env python

user_submitted = "0123456789abcdefghijklmnopqrstuvwxyz"

verify_arr = [193, 35, 9, 33, 1, 9, 3, 33, 9, 225]

user_arr = []

for char in user_submitted:

  # '<<' is left bit shift

  # '>>' is right bit shift

  # '|' is bit-wise or

  # '^' is bit-wise xor

  # '&' is bit-wise and

  user_arr.append( (((ord(char) << 5) | (ord(char) >> 3)) ^ 111) & 255 )

print user_arr

print "  "

 Rồi đối chiếu với mảng kia là xong!!