def extract_ref_l(ref):
"""
解析ref：长字符串
:param ref:
:return:
"""
logger.debug('extract ref begin')
if not ref or not isinstance(ref, str) or ref == '':
return None
ref = rc4_decrypt(ref, ref_pwd, a2b_hex)
logger.debug(u'ref = %r', ref)
if len(ref) <= 3:
#至少要求3字节
return None
head, acc_len, key_cipher_len = struct.unpack('>BBB', ref[:3])
logger.debug(u'head = %r, acc_len = %r, key_cipher_len = %r', head,
acc_len, key_cipher_len)
if len(ref) != 3 + acc_len + key_cipher_len + MAX_FILENAME_LEN:
return None
acc = ref[3:acc_len + 3]
key_cipher = ref[acc_len + 3:acc_len + 3 + key_cipher_len]
logger.debug(u'acc = %r, key_cipher = %r', acc, key_cipher)
logger.debug(u'rc4 decrypt result = %r',
rc4_decrypt(key_cipher, ref_pwd, None))
if acc != rc4_decrypt(key_cipher, ref_pwd, None):
return None
share, by_app = span_bits(head, 7, 6, 0)
logger.debug('extract ref end')
return share, by_app, acc, unpad(ref[-MAX_FILENAME_LEN:])
def decrypt(s, key, iv, seg_size, seg_ratio=3):
"""
:param seg_ratio: aes密文的长度必定为ratio的整数倍
"""
if not s or not isinstance(s, str):
return None
# 1->2 binascii, one seg_ratio
if 0 != len(s) % (2 * seg_ratio):
return None
_ = AES.new(key, AES.MODE_CFB, iv,
segment_size=seg_size).decrypt(binascii.a2b_hex(s))
# unpadding
return unpad(_)
def extract_tk_l(tk, ul):
"""
:param ul: 上传：长字符串
"""
logger.debug('extract tk begin')
if not tk or not isinstance(tk, str) or len(tk) <= 2:
logger.info('tk too short')
return None
tk = rc4_decrypt(tk, tk_pwd, a2b_hex)
logger.debug(u'tk = %r', tk)
rnd, val = tk[-2:]
val = rc4_decrypt(val, tk_pwd, None)
logger.debug('rnd = %r, val = %r', rnd, val)
rnd = struct.unpack('>B', rnd)[0]
val = struct.unpack('>B', val)[0]
logger.debug('rnd = %r, val = %r', rnd, val)
if rnd + 1 != val:
logger.warn('rnd={0} & val={1} unmatch'.format(rnd, val))
return None
head, acc_len = struct.unpack('>BB', tk[:2])
logger.debug('head = %r, acc_len = %r', head, acc_len)
if len(tk) != 2 + acc_len + 4 + MAX_FILENAME_LEN + 2:
logger.warn('tk len not ok')
return None
#10分钟有效
ts_offset = 2 + acc_len
t = struct.unpack('>I', tk[ts_offset:ts_offset + 4])[0]
now = time.time()
logger.debug('now = %r, t = %r', now, t)
if now - struct.unpack('>I', tk[ts_offset:ts_offset + 4])[0] >= 600:
logger.warn('tk timeout')
logger.debug('now = %r, t = %r', now, t)
return None
share, by_app, is_ul = span_bits(head, 7, 5, 0)
logger.debug('share = %r, by_app = %r, is_ul = %r, ul=%r', share, by_app,
is_ul, ul)
if is_ul != ul:
logger.warn('ul param invalid')
return None
logger.debug('extract tk end')
return share, by_app, tk[2:acc_len + 2], unpad(tk[ts_offset + 4:ts_offset +
4 + MAX_FILENAME_LEN])
def ecb_decrypt(text, key):
"""
decrypt request message
@param key: 服务器预先分配的20字节随机串，aes加密和hmac-sha1校验密钥相关
@param text: 待解密的文本，前32字节为aes解密后的密文，后40字节为相关hmac-sha1校验值
"""
if not key or not isinstance(key, str):
return None
if not text or not isinstance(text, str):
return None
text = binascii.unhexlify(text)
aes_after = AES.new(key, AES.MODE_ECB).decrypt(text)
return unpad(aes_after)