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Speedup the mac calculation on upload

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gissehel 2013-05-05 20:29:41 +02:00
parent c453a88b28
commit c2befcb87f
1 changed files with 17 additions and 18 deletions
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35
mega/mega.py
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@ -503,33 +503,30 @@ class Mega(object):
#generate random aes key (128) for file
ul_key = [random.randint(0, 0xFFFFFFFF) for _ in range(6)]
k_str = a32_to_str(ul_key[:4])
count = Counter.new(128, initial_value=((ul_key[4] << 32) + ul_key[5]) << 64)
aes = AES.new(a32_to_str(ul_key[:4]), AES.MODE_CTR, counter=count)
aes = AES.new(k_str, AES.MODE_CTR, counter=count)
file_mac = [0, 0, 0, 0]
upload_progress = 0
completion_file_handle = None
mac_str = '\0' * 16
mac_encryptor = AES.new(k_str, AES.MODE_CBC, mac_str)
iv_str = a32_to_str([ul_key[4], ul_key[5], ul_key[4], ul_key[5]])
for chunk_start, chunk_size in get_chunks(file_size):
chunk = input_file.read(chunk_size)
upload_progress += len(chunk)
#determine chunks mac
chunk_mac = [ul_key[4], ul_key[5], ul_key[4], ul_key[5]]
for i in range(0, len(chunk), 16):
encryptor = AES.new(k_str, AES.MODE_CBC, iv_str)
for i in range(0, len(chunk)-16, 16):
block = chunk[i:i + 16]
if len(block) % 16:
block += '\0' * (16 - len(block) % 16)
block = str_to_a32(block)
chunk_mac = [chunk_mac[0] ^ block[0], chunk_mac[1] ^ block[1],
chunk_mac[2] ^ block[2],
chunk_mac[3] ^ block[3]]
chunk_mac = aes_cbc_encrypt_a32(chunk_mac, ul_key[:4])
#our files mac
file_mac = [file_mac[0] ^ chunk_mac[0], file_mac[1] ^ chunk_mac[1],
file_mac[2] ^ chunk_mac[2],
file_mac[3] ^ chunk_mac[3]]
file_mac = aes_cbc_encrypt_a32(file_mac, ul_key[:4])
encryptor.encrypt(block)
i += 16
block = chunk[i:i + 16]
if len(block) % 16:
block += '\0' * (16 - len(block) % 16)
mac_str = mac_encryptor.encrypt(encryptor.encrypt(block))
#encrypt file and upload
chunk = aes.encrypt(chunk)
@ -541,6 +538,8 @@ class Mega(object):
# upload progress
print('{0} of {1} uploaded'.format(upload_progress, file_size))
file_mac = str_to_a32(mac_str)
#determine meta mac
meta_mac = (file_mac[0] ^ file_mac[1], file_mac[2] ^ file_mac[3])