def random_encrypt(self):
# randomly choose plaintext message from lines 0-9 in w8.txt
line_num = os.urandom(1)[0] % 10
f = open("w8.txt")
message = f.readlines()[line_num]
# un-base64 and encrypt message
message = base64.b64decode(message)
c_text = encrypt_cbc(message, self.key, self.iv)
return c_text, self.iv
def sanitizer(p):
# concatenate input string with prepend and append strings
prepend = "comment1=raining%20MCs;userdata="
append = ";comment2=%20like%20a%20sunny%20day%20tomorrow"
s = prepend + p + append
# quote out ";" and "=" characters
s = s.replace(";", "")
s = s.replace("=", "")
print("Sanitized plaintext: " + s)
# return encrypted string
c = encrypt_cbc(my_encode(s), key, iv)
return c
def encrypt(self, plaintext):
c_text = encrypt_cbc(plaintext, self.key, self.iv)
return c_text, self.iv
b_array = bytearray(my_encode(plaintext))
# randomly prepend 5-10 bytes
random_prepend = os.urandom(1)
num_prepend_bytes = 5 + random_prepend[0] % 6 # noOfPrependBytes
for i in range(0, num_prepend_bytes):
b_array.append(os.urandom(1)[0])
# randomly append 5-10 bytes
random_append = os.urandom(1)
num_append_bytes = 5 + random_append[0] % 6 # noOfAppendBytes
for j in range(0, num_append_bytes):
b_array.insert(0, os.urandom(1)[0])
# create modified plaintext
plaintext = bytes(b_array)
# encrypt
if mode == 0:
ciphertext = encrypt_ecb(plaintext, random_key, True)
else:
random_iv = os.urandom(16)
ciphertext = bytes(my_encode(encrypt_cbc(plaintext, random_key, random_iv)))
# ciphertext = bytes(test_encrypt(plaintext, random_key, random_iv))
# print detected mode
if detect_ecb(binascii.hexlify(ciphertext)):
print("ECB mode detected")
else:
print("CBC mode detected")
def bad_encrypt(self, plaintext):
return bytes(encrypt_cbc(plaintext, self.key, self.bad_iv), 'latin1')
# randomly prepend 5-10 bytes
random_prepend = os.urandom(1)
num_prepend_bytes = 5 + random_prepend[0] % 6 # noOfPrependBytes
for i in range(0, num_prepend_bytes):
b_array.append(os.urandom(1)[0])
# randomly append 5-10 bytes
random_append = os.urandom(1)
num_append_bytes = 5 + random_append[0] % 6 # noOfAppendBytes
for j in range(0, num_append_bytes):
b_array.insert(0, os.urandom(1)[0])
# create modified plaintext
plaintext = bytes(b_array)
# encrypt
if mode == 0:
ciphertext = encrypt_ecb(plaintext, random_key, True)
else:
random_iv = os.urandom(16)
ciphertext = bytes(
my_encode(encrypt_cbc(plaintext, random_key, random_iv)))
# ciphertext = bytes(test_encrypt(plaintext, random_key, random_iv))
# print detected mode
if repeated_block(binascii.hexlify(ciphertext)):
print("ECB mode detected")
else:
print("CBC mode detected")