def encrypt_random_choice(key):
selection = secret_messages[random.randint(0, len(secret_messages) - 1)]
init_vector = iv()
return (
cbc_encrypt(selection, key, init_vector),
init_vector,
)
def encrypt_kvps(content, key, iv):
full_content = (
'comment1=cooking%20MCs;userdata='
+ urllib.quote(content)
+ ';comment2=%20like%20a%20pound%20of%20bacon'
)
return cbc_encrypt(full_content, key, iv)
def test_challenge10(self):
ciphertext = base64_to_bytes(read('10.txt'))
key = 'YELLOW SUBMARINE'
iv = '\x00' * 16
plaintext = cbc_decrypt(ciphertext, key, iv)
ciphertext = cbc_encrypt(plaintext, key, iv)
plaintext2 = cbc_decrypt(ciphertext, key, iv)
self.assertEquals(plaintext, plaintext2)
def multimode_oracle(plaintext, mode):
tampered = random_padding() + plaintext + random_padding()
key = encryption_key()
if mode == 'ecb':
return ecb_encrypt(tampered, key)
elif mode == 'cbc':
return cbc_encrypt(tampered, key, iv())
raise ValueError('Unknown mode')
def echo(self, message):
s = pow(self.A, self.b, self.p)
key = Sha1Hash().update(to_bytes_le(s)).digest()[:16]
ciphertext = message[:-16]
iv = message[-16:]
plaintext = crypto.cbc_decrypt(ciphertext, key, iv)
self.messages.append(plaintext)
iv = crypto.iv()
return crypto.cbc_encrypt(plaintext, key, iv) + iv
def send(self, receiver, message):
self.messages.append(message)
B = receiver.handshake(self.p, self.g, self.A)
s = pow(B, self.a, self.p)
key = Sha1Hash().update(to_bytes_le(s)).digest()[:16]
iv = crypto.iv()
ciphertext = crypto.cbc_encrypt(message, key, iv) + iv
returned_message = receiver.echo(ciphertext)
returned_ciphertext = returned_message[:-16]
returned_iv = returned_message[-16:]
decrypted = crypto.cbc_decrypt(
returned_ciphertext,
key,
returned_iv
)
return decrypted
def GET(self):
msg = crypto.cbc_encrypt(secret, master_key).encode("hex")
return render.generic(form.Form(),"You eavesdropped the following message:",msg,False)
def encrypt_url(content, key):
return crypto.cbc_encrypt(full_content, key, key)