def test_ch17(self):
key = generate_random_key()
oracle = encryption_get_oracle_func(key, cbc_padding_oracle)
lst = [
"MDAwMDAwTm93IHRoYXQgdGhlIHBhcnR5IGlzIGp1bXBpbmc=",
"MDAwMDAxV2l0aCB0aGUgYmFzcyBraWNrZWQgaW4gYW5kIHRoZSBWZWdhJ3MgYXJlIHB1bXBpbic=",
"MDAwMDAyUXVpY2sgdG8gdGhlIHBvaW50LCB0byB0aGUgcG9pbnQsIG5vIGZha2luZw==",
"MDAwMDAzQ29va2luZyBNQydzIGxpa2UgYSBwb3VuZCBvZiBiYWNvbg==",
"MDAwMDA0QnVybmluZyAnZW0sIGlmIHlvdSBhaW4ndCBxdWljayBhbmQgbmltYmxl",
"MDAwMDA1SSBnbyBjcmF6eSB3aGVuIEkgaGVhciBhIGN5bWJhbA==",
"MDAwMDA2QW5kIGEgaGlnaCBoYXQgd2l0aCBhIHNvdXBlZCB1cCB0ZW1wbw==",
"MDAwMDA3SSdtIG9uIGEgcm9sbCwgaXQncyB0aW1lIHRvIGdvIHNvbG8=",
"MDAwMDA4b2xsaW4nIGluIG15IGZpdmUgcG9pbnQgb2g=",
"MDAwMDA5aXRoIG15IHJhZy10b3AgZG93biBzbyBteSBoYWlyIGNhbiBibG93"
]
for plaintext in lst:
#test funcs
ciphertext = produce_ciphertext(plaintext, key)
self.assertTrue(oracle(ciphertext))
self.assertEqual(
unpadpkcs7(break_cbc_padding_oracle(oracle, ciphertext)),
plaintext)
def test_ch25(self):
key = generate_random_key(16)
with open('static/25.txt', 'r') as myfile:
cipher = b64decode(myfile.read())
plaintext = unpadpkcs7(aes_ecb_decrypt(cipher, "YELLOW SUBMARINE"))
nonce = form_nonce(0)
ciphertext = aes_ctr_encrypt_decrypt(plaintext, key, nonce)
edit_func = partial(edit_ciphertext, key=key)
# test edit_ciphertext function
result = edit_ciphertext(ciphertext, key, 32, "YELLOW")
self.assertEquals(
result,
aes_ctr_encrypt_decrypt(plaintext[:32] + "YELLOW" + plaintext[38:],
key, nonce))
# break it
self.assertEquals(break_edit_ciphertext(ciphertext, edit_func),
plaintext)
def decryption_oracle(ciphertext, key, blocksize=16):
iv = ciphertext[:blocksize]
return unpadpkcs7(aes_cbc_decrypt(ciphertext[blocksize:], key, iv))
def decryption_oracle(ciphertext, key, blocksize=16):
iv = key
blocks = aes_cbc_decrypt(ciphertext, key, iv)
if not all(map(lambda x: x in range(0, 128), blocks)):
raise Not7BitAscii(blocks)
return unpadpkcs7(blocks)
def decryption_oracle(cipher, key):
return key_value_parse(unpadpkcs7(aes_ecb_decrypt(cipher, key)))
def test_ch10(self):
with open("static/10.txt", "r") as myfile:
cipher = b64decode(myfile.read())
key = "YELLOW SUBMARINE"
self.assertEqual(unpadpkcs7(aes_cbc_decrypt(cipher, key)), self.poem)