apppublic/appPublic/dataencoder.py

150 lines
4.1 KiB
Python
Raw Normal View History

2021-07-13 16:13:59 +08:00
try:
import ujson as json
except:
import json
from appPublic.rsa import RSA
from appPublic.rc4 import RC4
from appPublic.uniqueID import getID
import brotli
import zlib
import struct
DATA_TYPE_BYTES = 1
DATA_TYPE_STR = 2
DATA_TYPE_JSON = 3
class DataEncoder:
"""
security data packing - unpacking object
packs data:
encode data with random key's rc4 crypt algorithm,
encode rc4's key with receiver's public key
sign data with sender's private key
packs data using struct in follows order
0: data format(18 bytes)
1. datatype(c)
2. encoded data(length=len(d))
3. encoded_rc4key(length=len(k))
4. sign(signs from (0+1+2+3) data) (length=len(s))
5. compress data and return compressed dta
return packed data
unpacks data:
0. decompress data
1. get 18 bytes fmt data, erase tails b'0x00'
2. using fmt to unpack data[18:]
3. verify sign
4. decode k
5. decode data usig decoded k with rc4 algorithm
6. convert data type to origin data type
7. return converted data
"""
def __init__(self, myid, func_get_peer_pubkey, private_file=None):
self.myid = myid
self.func_get_peer_pubkey = func_get_peer_pubkey
self.public_keys = {}
self.private_file = private_file
self.rsa = RSA()
self.rc4 = RC4()
if self.private_file:
self.private_key = self.rsa.read_privatekey(self.private_file)
else:
self.private_key = rsa.create_privaatekey()
self.public_key = self.rsa.create_publickey(self.private_key)
def identify_datatype(self, data):
if isinstance(data, bytes):
return DATA_TYPE_BYTES, data
if isinstance(data, str):
return DATA_TYPE_STR, data.encode('utf-8')
data = json.dumps(data).encode('utf-8')
return DATA_TYPE_JSON, data
def my_text_publickey(self):
pk = self.public_key()
return self.rsa.publickeyText(pk)
def exist_peer_publickeys(self, peer_id):
return True if self.public_keys.get(peer_id, False) else False
def set_peer_pubkey(self, peer_id, pubkey):
self.public_keys[peer_id] = pubkey
def get_peer_text_pubkey(self, peer_id):
pk = self.get_peer_pubkey()
txtpk = self.rsa. publickeyText(pk)
return txtpk
def set_peer_text_pubkey(self, peer_id, text_pubkey):
pk = self.rsa.publickeyFromText(text_pubkey)
self.set_peer_pubkey(peer_id, pk)
def get_peer_pubkey(self, peer_id):
pubkey = self.public_keys.get(peer_id)
if not pubkey:
try:
self.func_get_peer_pubkey(peer_id)
except:
raise Exception('Can not get peer public key(%s)')
pubkey = self.public_keys.get(peer_id)
return pubkey
def pack(self, peer_id, data):
pk = self.get_peer_pubkey(peer_id)
t, d = self.identify_datatype(data)
d, k = self.encode_data(pk, d)
f = 'b%05ds%03ds' % (len(d), len(k))
f1 = f + '256s'
pd1 = struct.pack('18s', f1.encode('utf-8'))
pd2 = struct.pack(f, t, d, k)
pd = pd1 + pd2
s = self.sign_data(pd)
pd += s
self.pack_d = [t,d,k,s]
origin_len = len(pd)
pd = brotli.compress(pd)
pdz = zlib.compress(pd)
print('brotli lenght=%d, zlib length=%d, origin length=%d' % \
(len(pd), len(pdz), origin_len)
)
return pd
def unpack(self, peer_id, data):
data = brotli.decompress(data)
org_data = data
pk = self.get_peer_pubkey(peer_id)
f = data[:18]
f.strip(b'0x00')
f = f.decode('utf-8')
data = data[18:]
t, d, k, s = struct.unpack(f, data)
self.unpack_d = [t,d,k,s]
data1 = org_data[:org_data.index(s)]
if not self.verify_sign(data1, s, pk):
raise Exception('data sign verify failed')
data = self.decode_data(d, k)
if t == DATA_TYPE_BYTES:
return data
if t == DATA_TYPE_STR:
return data.decode('utf-8')
return json.loads(data)
def encode_data(self, peer_pubkey, data):
key = getID()
if isinstance(key, str):
key = key.encode('utf-8')
ctext = self.rc4.encode_bytes(data, key)
encoded_key = self.rsa.encode_bytes(peer_pubkey, key)
print('key length compare,', len(key), len(encoded_key))
return ctext, encoded_key
def sign_data(self, data):
return self.rsa.sign_bdata(self.private_key, data)
def decode_data(self, data, encoded_key):
key = self.rsa.decode_bytes(self.private_key, encoded_key)
return self.rc4.decode_bytes(data, key)
def verify_sign(self, data, sign, peer_pubkey):
return self.rsa.check_sign_bdata(peer_pubkey, data, sign)