Arvind Shima | March 17,2022
| Tables | Description |
|---|---|
| Category | Reverse Engineering |
| Challenge Name | patchme.py |
| Points | 100 |
Can you get the flag? Run this Python program in the same directory as this encrypted flag.
### THIS FUNCTION WILL NOT HELP YOU FIND THE FLAG --LT ########################
def str_xor(secret, key):
#extend key to secret length
new_key = key
i = 0
while len(new_key) < len(secret):
new_key = new_key + key[i]
i = (i + 1) % len(key)
return "".join([chr(ord(secret_c) ^ ord(new_key_c)) for (secret_c,new_key_c) in zip(secret,new_key)])
###############################################################################
flag_enc = open('flag.txt.enc', 'rb').read()
def level_1_pw_check():
user_pw = input("Please enter correct password for flag: ")
if( user_pw == "ak98" + \
"-=90" + \
"adfjhgj321" + \
"sleuth9000"):
print("Welcome back... your flag, user:")
decryption = str_xor(flag_enc.decode(), "utilitarian")
print(decryption)
return
print("That password is incorrect")
level_1_pw_check()In this challenge have defined a function with condition. I modified the operator == to != and Run the program.
def str_xor(secret, key):
new_key = key
i = 0
while len(new_key) < len(secret):
new_key = new_key + key[i]
i = (i + 1) % len(key)
return "".join([chr(ord(secret_c) ^ ord(new_key_c)) for (secret_c,new_key_c) in zip(secret,new_key)])
flag_enc = open('flag.txt.enc', 'rb').read()
def level_1_pw_check():
user_pw = input("Please enter correct password for flag: ")
if( user_pw != "ak98" + \
"-=90" + \
"adfjhgj321" + \
"sleuth9000"):
print("Welcome back... your flag, user:")
decryption = str_xor(flag_enc.decode(), "utilitarian")
print(decryption)
return
print("That password is incorrect")
level_1_pw_check()
picoCTF{p47ch1ng_l1f3_h4ck_c4a4688b}