欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

Python中实现的RC4算法

程序员文章站 2023-11-18 20:53:28
闲暇之时,用Python实现了一下RC4算法 编码 UTF-8 class 方式 #/usr/bin/python #coding=utf-8 imp...

闲暇之时,用Python实现了一下RC4算法

编码 UTF-8

class 方式

#/usr/bin/python
#coding=utf-8

import sys,os,hashlib,time,base64
class rc4:

  def __init__(self,public_key = None,ckey_lenth = 16):
    self.ckey_lenth = ckey_lenth
    self.public_key = public_key or 'none_public_key'
    key = hashlib.md5(self.public_key).hexdigest()
    self.keya = hashlib.md5(key[0:16]).hexdigest()
    self.keyb = hashlib.md5(key[16:32]).hexdigest()
    self.keyc = ''

  def encode(self,string):
    self.keyc = hashlib.md5(str(time.time())).hexdigest()[32 - self.ckey_lenth:32]
    string = '0000000000' + hashlib.md5(string + self.keyb).hexdigest()[0:16] + string
    self.result = ''
    self.docrypt(string)
    return self.keyc + base64.b64encode(self.result)

  def decode(self,string):
    self.keyc = string[0:self.ckey_lenth]
    string = base64.b64decode(string[self.ckey_lenth:])
    self.result = ''
    self.docrypt(string)
    result = self.result
    if (result[0:10] == '0000000000' or int(result[0:10]) - int(time.time()) > 0) and result[10:26] == hashlib.md5(result[26:] + self.keyb).hexdigest()[0:16]:
      return result[26:]
    else:
      return None

  def docrypt(self,string):
    string_lenth = len(string)
    result = ''
    box = list(range(256))
    randkey = []

    cryptkey = self.keya + hashlib.md5(self.keya + self.keyc).hexdigest()
    key_lenth = len(cryptkey)

    for i in xrange(255):
      randkey.append(ord(cryptkey[i % key_lenth]))

    for i in xrange(255):
      j = 0
      j = (j + box[i] + randkey[i]) % 256
      tmp = box[i]
      box[i] = box[j]
      box[j] = tmp

    for i in xrange(string_lenth):
      a = j = 0
      a = (a + 1) % 256
      j = (j + box[a]) % 256
      tmp = box[a]
      box[a] = box[j]
      box[j] = tmp
      self.result += chr(ord(string[i]) ^ (box[(box[a] + box[j]) % 256]))

测试:

rc = rc4('nishidahuaidan')
string = '我在这里呢,你在那里呢'
print(string)
str = rc.encode(string)
print(str)
str = rc.decode(str)
print(str)

function方式

#/usr/bin/python
#coding=utf-8

import sys,os,hashlib,time,base64

def rc4(string, op = 'encode', public_key = 'ddd', expirytime = 0):
  ckey_lenth = 4
  public_key = public_key and public_key or ''
  key = hashlib.md5(public_key).hexdigest()
  keya = hashlib.md5(key[0:16]).hexdigest()
  keyb = hashlib.md5(key[16:32]).hexdigest()
  keyc = ckey_lenth and (op == 'decode' and string[0:ckey_lenth] or hashlib.md5(str(time.time())).hexdigest()[32 - ckey_lenth:32]) or ''
  cryptkey = keya + hashlib.md5(keya + keyc).hexdigest()
  key_lenth = len(cryptkey)
  string = op == 'decode' and base64.b64decode(string[4:]) or '0000000000' + hashlib.md5(string + keyb).hexdigest()[0:16] + string
  string_lenth = len(string)

  result = ''
  box = list(range(256))
  randkey = []

  for i in xrange(255):
    randkey.append(ord(cryptkey[i % key_lenth]))

  for i in xrange(255):
    j = 0
    j = (j + box[i] + randkey[i]) % 256
    tmp = box[i]
    box[i] = box[j]
    box[j] = tmp

  for i in xrange(string_lenth):
    a = j = 0
    a = (a + 1) % 256
    j = (j + box[a]) % 256
    tmp = box[a]
    box[a] = box[j]
    box[j] = tmp
    result += chr(ord(string[i]) ^ (box[(box[a] + box[j]) % 256]))

  if op == 'decode':
    if (result[0:10] == '0000000000' or int(result[0:10]) - int(time.time()) > 0) and result[10:26] == hashlib.md5(result[26:] + keyb).hexdigest()[0:16]:
      return result[26:]
    else:
      return None
  else:
    return keyc + base64.b64encode(result)

测试:

string = '我在这里呢,你在那里呢'
print(string)
str = rc4(string,'encode')
print(str)
rc = rc4(str,'decode')
print(rc)