Skip to content

Instantly share code, notes, and snippets.

@ivanovanton

ivanovanton/leha krasava

Created March 13, 2017 17:41
Show Gist options
  • Save ivanovanton/6461155f315a3a36c66d174f690eeb45 to your computer and use it in GitHub Desktop.
Save ivanovanton/6461155f315a3a36c66d174f690eeb45 to your computer and use it in GitHub Desktop.
Download ZIP
Raw
leha krasava
def task_1(s, size):
try:
if (len(s) % int(size) == 0 ):
s += chr(int(size))*int(size)
return s
else:
s += chr(int(size) - len(s) % int(size))*(int(size) - len(s) % int(size))
return s
except:
return "Некорректные параметры"
def task_2(s):
try:
byte = s[len(s)-1]
if (s.rfind(byte*ord(byte)) == len(s)-ord(byte)):
return (s[:len(s)-ord(byte)])
block = s[len(s)-4:]
if (s.rfind(block*int(block[len(block)-1])) == len(s)-len(block)*int(block[len(block)-1])):
return (s[:len(s)-len(block)*int(block[len(block)-1])])
else:
return 'Строка не имеет дополнения или имеет неправильное дополнение'
except:
return 'Строка не имеет дополнения или имеет неправильное дополнение'
#Задание 1. Реализация дополнения блока до нужной длины по стандарту PKCS7
try:
k = int(input("Введите длину блока: "))
text = input("Введите открытый текст: ")
except Exception:
print("Введены некорректные данные")
print("Результат: ")
task_1(k, text)
#YELLOW SUBMARINE
#Задание 2.Проверка дополнения PKCS7
block = 'ICEICEBABY\x04\x04\x04\x04'
res = task_2(block)
print("Результат: " + str(res))
#ICE ICE BABY\x05\x05\x05\x05
from Crypto import Random
from Crypto.Cipher import AES
import base64
IV = Random.new().read(16)
key = Random.new().read(16)
def encrypt(message, mode):
aes = AES.new(key, mode, IV)
return aes.encrypt(message)
def decrypt(encrypted, mode):
aes = AES.new(key, mode, IV)
return aes.decrypt(encrypted)
#Задание 3. Атака на CBCрежим. Bit-flipping
def func1(text):
mode = AES.MODE_CBC
text = text.replace('=', '').replace(';', '')
plaintext = "comment1=cooking%20MCs;userdata=" + text + "comment2=%20like%20a%20pound%20of%20bacon"
plaintext = task1(16, plaintext)
ciphertext = encrypt(plaintext, mode)
return ciphertext, plaintext
def task3():
mode = AES.MODE_CBC
my_str = "admin=true"
n = 64
text = str(input("Введите текст: "))
ciphertext, plaintext = func1(text)
ciphertext = bytearray(ciphertext)
for i in range(len(my_str)):
ciphertext[n+i-16] = ciphertext[n+i-16] ^ ord(plaintext[n+i]) ^ ord(my_str[i])
return decrypt(bytes(ciphertext), mode)
#Задание 4.Функция детектирования режима ECB(функция оракул)
import random
def task4(text):
if random.randint(0, 1) == 0:
mode = AES.MODE_CBC
else:
mode = AES.MODE_ECB
text = text.replace('=', '').replace(';', '')
pre = ""
suf = ""
for i in range(random.randint(5, 10)):
pre += chr(random.randint(65, 96))
for i in range(random.randint(5, 10)):
suf += chr(random.randint(65, 96))
plaintext = task_1(16, pre + text + suf)
ciphertext = encrypt(plaintext, mode)
my_str = "detect"
n = 16
ciphertext = bytearray(ciphertext)
for i in range(len(my_str)):
ciphertext[n+i-16] = ciphertext[n+i-16] ^ ord(plaintext[n+i]) ^ ord(my_str[i])
q = decrypt(bytes(ciphertext), mode)
if q.find(b"detect") > 0:
return "CBC"
else:
return "ECB"
text = input("Введите текст: ")
res = task4(text)
print("Режим шифрования: " + str(res))
from Crypto import Random
from Crypto.Cipher import AES
IV = Random.new().read(16)
key = Random.new().read(16)
def encrypt(message):
aes = AES.new(key, AES.MODE_CBC, IV)
return aes.encrypt(message)
def decrypt(encrypted):
aes = AES.new(key, AES.MODE_CBC, IV)
return aes.decrypt(encrypted)
#Побайтовое дешифрование режима ECB
import base64
from Crypto import Random
from Crypto.Cipher import AES
unknownStrBase64 = "Um9sbGluJyBpbiBteSA1LjAKV2l0aCBteSByYWctdG9wIGRvd24gc28gbXkgaGFpciBjYW4gYmxvdwpUaGUgZ2lybGllcyBvbiBzdGFuZGJ5IHdhdmluZyBqdXN0IHRvIHNheSBoaQpEaWQgeW91IHN0b3A/IE5vLCBJIGp1c3QgZHJvdmUgYnkK"
unknownStr = task_1(base64.b64decode(unknownStrBase64).decode('utf-8'), 16)
key = Random.new().read(16)
mode = AES.MODE_ECB
def AES_128_ECB(text, unknownStr):
aes = AES.new(key, AES.MODE_ECB)
return aes.encrypt(task_1(text + unknownStr, 16))
#Функция возвращает один блок
def decrypt(block):
dec = ''
text = 'A'*15
for i in range(16):
for k in range(256):
if (AES_128_ECB(text, block)[:16] == encrypt(text + chr(k), mode)):
dec += chr(k)
break
text = text[1:] + chr(k)
block = block[1:]
return dec
dec = ''
for i in range(0, len(unknownStr), 16):
dec += decrypt(unknownStr[i:i+16])
print(task_2(dec))
import urllib.parse as url
from Crypto import Random
from Crypto.Cipher import AES
def string_to_object(string):
return encrypt(task_1(profile_for(dict(url.splitvalue(s) for s in string.split('&'))), 16))
def profile_for(email):
return url.unquote(url.urlencode([('email',email),('uid',10),('role','user')]))
def encrypt(message):
aes = AES.new(key, AES.MODE_ECB)
return aes.encrypt(message)
def decrypt(encrypted):
aes = AES.new(key, AES.MODE_ECB)
return aes.decrypt(encrypted)
email = '[email protected]'
profile = profile_for(email)
index = profile.find('user') // 16 * 16
modified_block = task_1(profile[index:].replace('user', 'admin'), 16)
modified_enc = enc[:index] + encrypt(modified_block)
string_to_object(task_2(decrypt(bytes(modified_enc)).decode('utf-8')))
random_prefix = ''
for i in range(random.randint(0, 100)):
random_prefix += chr(random.randint(65, 90))
unknownStrBase64 = "Um9sbGluJyBpbiBteSA1LjAKV2l0aCBteSByYWctdG9wIGRvd24gc28gbXkgaGFpciBjYW4gYmxvdwpUaGUgZ2lybGllcyBvbiBzdGFuZGJ5IHdhdmluZyBqdXN0IHRvIHNheSBoaQpEaWQgeW91IHN0b3A/IE5vLCBJIGp1c3QgZHJvdmUgYnkK"
unknownStr = task_1(base64.b64decode(unknownStrBase64).decode('utf-8'), 16)
key = Random.new().read(16)
def AES_128_ECB(random_prefix, text, unknownStr):
aes = AES.new(key, AES.MODE_ECB)
return aes.encrypt(task_1(random_prefix + text + unknownStr, 16))
def decrypt(block):
dec = ''
text = 'A'*(len(random_prefix)//16*16 + 16 - len(random_prefix) -1)
for i in range(16):
for k in range(256):
if (AES_128_ECB(random_prefix, text, block)[:len(random_prefix) + len(text) + 1] == encrypt(random_prefix + text + chr(k))):
dec += chr(k)
break
text = text[1:] + chr(k)
block = block[1:]
return dec
dec = ''
for i in range(0, len(unknownStr), 16):
dec += decrypt(unknownStr[i:i+16])
task_2(dec)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment