def send_message_B(ciphertext, iv):
global s_B, A_B, b, p
s_B = pow(A_B, b, p)
key = hashes.SHA1(util.int_to_bytes(s_B))
key = util.get_ith_block(key, 0, BLOCK_SIZE)
plaintext = util.cbc_decrypt(ciphertext, key, iv)
assert plaintext == MESSAGE
iv = util.random_byte_string(BLOCK_SIZE)
return (util.cbc_encrypt(plaintext, key, iv), iv)
def send_message_A(B):
global s_A, a, p, B_A
B_A = B
s_A = pow(B_A, a, p)
msg = MESSAGE
key = hashes.SHA1(util.int_to_bytes(s_A))
key = util.get_ith_block(key, 0, BLOCK_SIZE)
iv = util.random_byte_string(BLOCK_SIZE)
return (util.cbc_encrypt(msg, key, iv), iv)
def ecb_cbc_oracle(data):
prefix = util.random_byte_string(random.randint(5, 10))
suffix = util.random_byte_string(random.randint(5, 10))
key = util.random_byte_string(16)
data = util.padding(prefix + data + suffix, 16)
mode = random.randint(0, 1)
if mode == 1:
return util.ecb_encrypt(data, key), mode
else:
iv = util.random_byte_string(16)
return util.cbc_encrypt(data, key, iv), mode
def block_encrypt(p):
key = util.random_byte_string(16)
iv = util.random_byte_string(16)
return util.cbc_encrypt(p, key, iv=iv)
def cbc_encrypt(): plaintext = b'The quick brown fox jumps over a lazy dog.' return util.cbc_encrypt(plaintext, key, iv = key)
def cbc_encrypt_surround(chosen): prefix = b'comment1=cooking%20MCs;userdata=' secret = b';comment2=%20like%20a%20pound%20of%20bacon' chosen = chosen.replace(b';', b'').replace(b'=',b'') return util.cbc_encrypt(prefix + chosen + secret, key)
def cbc_encrypt_special():
chosen = plaintext_list[random.randint(0, len(plaintext_list) - 1)]
chosen = base64.b64decode(chosen)
return util.cbc_encrypt(chosen, key, iv)