apppublic/appPublic/rc4.py

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# -*- coding: utf-8 -*-
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import time
import datetime
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import random, base64
from hashlib import sha1
class RC4:
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def __init__(self,data_coding='utf8'):
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self.bcoding = 'iso-8859-1'
self.dcoding = data_coding
self.salt = b'AFUqx9WZuI32lnHk'
def _crypt(self,data,key):
"""RC4 algorithm return bytes"""
x = 0
box = [i for i in range(256) ]
for i in range(256):
x = (x + box[i] + key[i % len(key)]) % 256
box[i], box[x] = box[x], box[i]
x = y = 0
out = []
for char in data:
x = (x + 1) % 256
y = (y + box[x]) % 256
box[x], box[y] = box[y], box[x]
out.append(chr(char ^ box[(box[x] + box[y]) % 256]))
return ''.join(out).encode(self.bcoding)
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def encode_bytes(self, bdata, key):
a = sha1(key + self.salt)
k = a.digest()
data = self.salt + self._crypt(bdata, k)
return data
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def encode(self,data, key,encode=base64.b64encode, salt_length=16):
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"""RC4 encryption with random salt and final encoding"""
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if type(data)==type(''):
data = data.encode(self.dcoding)
key = key.encode(self.bcoding)
self.encode_bytes(data, key)
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if encode:
data = encode(data)
return data.decode(self.dcoding)
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def decode_bytes(self, data, key):
salt_length = 16
salt = data[:salt_length]
a = sha1(key + self.salt)
k = a.digest() #.decode('iso-8859-1')
r = self._crypt(data[salt_length:], k)
return r
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def decode(self,data, key,decode=base64.b64decode, salt_length=16):
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"""RC4 decryption of encoded data"""
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if type(data)==type(''):
data = data.encode(self.dcoding)
key = key.encode(self.bcoding)
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if decode:
data = decode(data)
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r = self.decode_bytes(data, key)
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return r.decode(self.dcoding)
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class KeyChain(object):
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def __init__(self, seed_str, crypter=None, keylen=23, period=600, threshold=60):
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self.seed_str = seed_str
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self.period = int(period)
self.threshold = int(threshold)
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self.crypter = crypter
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if crypter is None:
self.crypter = RC4()
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self.keylen = keylen
self.keypool = {
}
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delta = datetime.timedelta(0)
self.timezone = datetime.timezone(delta, name='gmt')
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def is_near_bottom(self, indicator=None):
ts = time.time()
i = indicator
if i is None:
i = self.get_indicator(ts)
if i + self.threshold > ts:
return True
return FalseTrue
def is_near_top(self, indicator=None):
ts = time.time()
i = indicator
if i is None:
i = self.get_indicator(ts)
if i + self.period - self.threshold < ts:
return True
return False
def get_indicator(self, ts=None):
if ts is None:
ts = time.time()
return int(ts / self.period) * self.period
def genKey(self, indicator):
vv = indicator
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if self.keypool.get(vv):
return self.keypool[vv]
v = vv
k1 = 0
k = ''
m = len(self.seed_str)
while k1 < self.keylen:
j = v % self.keylen
v = v - (j + k1) * m + self.keylen
k = k + self.seed_str[j]
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k1 += self.threshold / 2
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key = k.encode('utf-8')
self.keypool[vv] = key
dates = [ d for d in self.keypool.keys() ]
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for d in dates:
if d < indicator - self.period:
del self.keypool[d]
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return key
def encode(self, text):
bdata = text.encode('utf-8')
return self.encode_bytes(bdata)
def encode_bytes(self, bdata):
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indicator = self.get_indicator()
key = self.genKey(indicator)
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data = key + bdata
return self.crypter.encode_bytes(data, key)
def _decode(self, data, key):
d = self.crypter.decode_bytes(data, key)
if d[:len(key)] == key:
return d[len(key):]
return None
def decode_bytes(self, data):
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indicator = self.get_indicator()
key = self.genKey(indicator)
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d = self._decode(data, key)
if d is not None:
return d
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if self.is_near_bottom(indicator):
indicator -= self.period
key = self.genKey(indicator)
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return self._decode(data, key)
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if self.is_near_top(indicator):
indicator += self.period
key = self.genKey(indicator)
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return self._decode(data, key)
return None
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def decode(self, data):
d = self.decode_bytes(data)
if d is None:
return None
return d.decode('utf-8')
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if __name__=='__main__':
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# 需要加密的数据长度没有限制
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# 密钥
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data=b"231r3 feregrenerjk gkht324g8924gnfw k;ejkvwkjerv"
key = b'123456'
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rc4 = RC4()
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kc = KeyChain('in the heaven, we are equal', rc4)
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print(data)
# 加码
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encoded_data = kc.encode_bytes(data)
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print(encoded_data,len(encoded_data) )
# 解码
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decoded_data = kc.decode_bytes(encoded_data)
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print(data, decoded_data, decoded_data==data)