def edit_fast(cipher, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
text = Crypto.decrypt_aes(
cipher, key, AES.MODE_CTR, counter=counter)
text = newtext
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
def edit(cipher, offset, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
text = Crypto.decrypt_aes(
cipher, key, AES.MODE_CTR, counter=counter)
text = text[:offset] + newtext + text[offset + 1:]
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
def edit_fast(cipher, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
text = Crypto.decrypt_aes(cipher,
key,
AES.MODE_CTR,
counter=counter)
text = newtext
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
def edit(cipher, offset, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
text = Crypto.decrypt_aes(cipher,
key,
AES.MODE_CTR,
counter=counter)
text = text[:offset] + newtext + text[offset + 1:]
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
def test_break_random_access_read_write(self):
"""Challenge 25"""
f = open('data/25.txt')
data = f.read()
f.close()
key = 'YELLOW SUBMARINE'
known = Crypto.decrypt_aes(base64.b64decode(data), key, AES.MODE_ECB)
seed = 23232232;
def edit(cipher, offset, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
text = Crypto.decrypt_aes(
cipher, key, AES.MODE_CTR, counter=counter)
text = text[:offset] + newtext + text[offset + 1:]
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
def edit_fast(cipher, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
text = Crypto.decrypt_aes(
cipher, key, AES.MODE_CTR, counter=counter)
text = newtext
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
counter = Crypto.gen_aes_stream_counter_mt19973(seed);
cipher = Crypto.encrypt_aes(known, key, AES.MODE_CTR, counter=counter)
text = edit_fast(cipher, cipher)
# replacing text with cipher is same is decrypting cipher.
#for i in range(len(cipher)):
# text += edit(cipher, i, cipher[i])[i]
self.assertEqual(known, text)
def has_admin(cipher):
"""Checks if cipher has admin."""
counter = Crypto.gen_aes_stream_counter_mt19973(3453243)
text = Crypto.decrypt_aes(cipher,
key,
AES.MODE_CTR,
counter=counter)
return text.find(';admin=true;') != -1
def test_ctr_bit_flipping(self):
"""Challenge 26"""
prefix = "comment1=cooking%20MCs;userdata="
suffix = ";comment2=%20like%20a%20pound%20of%20bacon"
counter = Crypto.gen_aes_stream_counter_mt19973(3453243);
oracle, key = Crypto.generate_aes_oracle(
prefix, suffix, AES.MODE_CTR, urllib.quote, 16, counter=counter)
def has_admin(cipher):
"""Checks if cipher has admin."""
counter = Crypto.gen_aes_stream_counter_mt19973(3453243);
text = Crypto.decrypt_aes(cipher, key, AES.MODE_CTR, counter=counter)
return text.find(';admin=true;') != -1
self.assertTrue(Crypto.flip_cipher_to_add_admin_ctr(oracle, has_admin))
def test_ctr_bit_flipping(self):
"""Challenge 26"""
prefix = "comment1=cooking%20MCs;userdata="
suffix = ";comment2=%20like%20a%20pound%20of%20bacon"
counter = Crypto.gen_aes_stream_counter_mt19973(3453243)
oracle, key = Crypto.generate_aes_oracle(prefix,
suffix,
AES.MODE_CTR,
urllib.quote,
16,
counter=counter)
def has_admin(cipher):
"""Checks if cipher has admin."""
counter = Crypto.gen_aes_stream_counter_mt19973(3453243)
text = Crypto.decrypt_aes(cipher,
key,
AES.MODE_CTR,
counter=counter)
return text.find(';admin=true;') != -1
self.assertTrue(Crypto.flip_cipher_to_add_admin_ctr(oracle, has_admin))
def test_break_random_access_read_write(self):
"""Challenge 25"""
f = open('data/25.txt')
data = f.read()
f.close()
key = 'YELLOW SUBMARINE'
known = Crypto.decrypt_aes(base64.b64decode(data), key, AES.MODE_ECB)
seed = 23232232
def edit(cipher, offset, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
text = Crypto.decrypt_aes(cipher,
key,
AES.MODE_CTR,
counter=counter)
text = text[:offset] + newtext + text[offset + 1:]
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
def edit_fast(cipher, newtext):
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
text = Crypto.decrypt_aes(cipher,
key,
AES.MODE_CTR,
counter=counter)
text = newtext
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
return Crypto.encrypt_aes(text, key, AES.MODE_CTR, counter=counter)
counter = Crypto.gen_aes_stream_counter_mt19973(seed)
cipher = Crypto.encrypt_aes(known, key, AES.MODE_CTR, counter=counter)
text = edit_fast(cipher, cipher)
# replacing text with cipher is same is decrypting cipher.
#for i in range(len(cipher)):
# text += edit(cipher, i, cipher[i])[i]
self.assertEqual(known, text)
def has_admin(cipher):
"""Checks if cipher has admin."""
counter = Crypto.gen_aes_stream_counter_mt19973(3453243);
text = Crypto.decrypt_aes(cipher, key, AES.MODE_CTR, counter=counter)
return text.find(';admin=true;') != -1
