python注册码实现（python实现Virginia无密钥解密）

python注册码实现

python实现Virginia无密钥解密

本文实例为大家分享了Virginia无密钥解密的具体代码，供大家参考，具体内容如下

加密

virginia加密是一种多表替换加密方法，通过这种方法，可以有效的解决单表替换中无法应对的字母频度攻击。这种加密方法最重要的就是选取合适的密钥，一旦密钥被公开，保密性也就无从谈起。结合virginia加密原理，给出使用python实现的代码

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plainText = "whenigotthethemeithoughtofgooglesartificialintelligencealphagothisprogramoverthebestofhumanplayeriwanttoaskwhenscienceandtechnologycontinuetodevelopwehumanbeingswillbewhatpositionweshouldrealizethatthedevelopmentofscienceandtechnologyisirreversibleanditconstituteaprimaryprductiveforcebutmanmustkeeppacewiththetimestoenhancetheablitytocontrol" # 密文 alphabet = "abcdefghijklmnopqrstuvwxyz" # 26个字母 cipherText = ""; key = "helloworld" # 密钥 keyLen = len(key) plainTextLen = len(plainText) j = 0 for i in range(0,plainTextLen):  j = i%keyLen  keyNum = alphabet.index(key[j])  plainNum = alphabet.index(plainText[i])  plainTemp = alphabet[(keyNum*plainNum)%26] # 密钥对明文作用  cipherText += plainTemp print(cipherText)

解密

重点谈谈解密部分。这里的解密主要分为获取密钥长度，根据密钥长度获取密钥，根据密钥获取明文三个部分。

获取密钥长度

使用暴力破解密钥长度的方法，循环遍历可能的密钥长度。每次循环中，记录在这种密钥长度下重复相隔密钥长度密文的次数，从理论上来讲，次数最多的那个密钥长度，最有可能正确。当密文长度足够长时，正确的可能性很高。给出获取密钥长度的python函数代码：

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def getKeyLen(cipherText): # 获取密钥长度  keylength = 1  maxCount = 0  for step in range(3,18): # 循环密钥长度   count = 0   for i in range(step,len(cipherText)-step):    if cipherText[i] == cipherText[i+step]:      count += 1   if count>maxCount: # 每次保存最大次数的密钥长度    maxCount = count    keylength = step  return keylength # 返回密钥长度

获取密钥

当已经获取密钥长度之后，我们可以通过分组将相同密钥作用下的密文进行分组，在每一组中，都是一个简单的单表替换加密。在这种情况下，我们通过重合指数法破解密钥，给出获取密钥部分的python函数代码：

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def getKey(text,length): # 获取密钥  key = [] # 定义空白列表用来存密钥  alphaRate =[0.08167,0.01492,0.02782,0.04253,0.12705,0.02228,0.02015,0.06094,0.06996,0.00153,0.00772,0.04025,0.02406,0.06749,0.07507,0.01929,0.0009,0.05987,0.06327,0.09056,0.02758,0.00978,0.02360,0.0015,0.01974,0.00074]  matrix =textToList(text,length)  for i in range(length):   w = [row[i] for row in matrix] #获取每组密文   li = countList(w)   powLi = [] #算乘积   for j in range(26):    Sum = 0.0    for k in range(26):     Sum += alphaRate[k]*li[k]    powLi.append(Sum)    li = li[1:]+li[:1]#循环移位   Abs = 100   ch = ''   for j in range(len(powLi)):     if abs(powLi[j] -0.065546)<Abs: # 找出最接近英文字母重合指数的项      Abs = abs(powLi[j] -0.065546) # 保存最接近的距离，作为下次比较的基准      ch = chr(j+97)   key.append(ch)  return key

 破解明文

在已知密钥和明文的基础上，我们很容易就可以得到明文，给出python代码：

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def virginiaCrack(cipherText): # 解密函数  length = getKeyLen(cipherText) #得到密钥长度  key = getKey(cipherText,length) #找到密钥  keyStr = ''  for k in key:   keyStr+=k  print('the Key is:',keyStr)  plainText = ''  index = 0  for ch in cipherText:   c = chr((ord(ch)-ord(key[index%length]))%26+97)   plainText += c   index+=1  return plainText # 返回明文

代码

这是解密部分的全部代码，注意需要自己添加密文文件的位置

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def virginiaCrack(cipherText): # 解密函数  length = getKeyLen(cipherText) #得到密钥长度  key = getKey(cipherText,length) #找到密钥  keyStr = ''  for k in key:   keyStr+=k  print('the key:',keyStr)  plainText = ''  index = 0  for ch in cipherText:   c = chr((ord(ch)-ord(key[index%length]))%26+97)   plainText += c   index+=1  return plainText def openfile(fileName): # 读文件  file = open(fileName,'r')  text = file.read()  file.close();  text = text.replace('\n','')  return text   def getKeyLen(cipherText): # 获取密钥长度  keylength = 1  maxCount = 0  for step in range(3,18): # 循环密钥长度   count = 0   for i in range(step,len(cipherText)-step):    if cipherText[i] == cipherText[i+step]:      count += 1   if count>maxCount:    maxCount = count    keylength = step  return keylength   def getKey(text,length): # 获取密钥  key = [] # 定义空白列表用来存密钥  alphaRate =[0.08167,0.01492,0.02782,0.04253,0.12705,0.02228,0.02015,0.06094,0.06996,0.00153,0.00772,0.04025,0.02406,0.06749,0.07507,0.01929,0.0009,0.05987,0.06327,0.09056,0.02758,0.00978,0.02360,0.0015,0.01974,0.00074]  matrix =textToList(text,length)  for i in range(length):   w = [row[i] for row in matrix] #获取每组密文   li = countList(w)   powLi = [] #算乘积   for j in range(26):    Sum = 0.0    for k in range(26):     Sum += alphaRate[k]*li[k]    powLi.append(Sum)    li = li[1:]+li[:1]#循环移位   Abs = 100   ch = ''   for j in range(len(powLi)):     if abs(powLi[j] -0.065546)<Abs: # 找出最接近英文字母重合指数的项      Abs = abs(powLi[j] -0.065546) # 保存最接近的距离，作为下次比较的基准      ch = chr(j+97)   key.append(ch)  return key      def countList(lis): # 统计字母频度  li = []  alphabet = [chr(i) for i in range(97,123)]  for c in alphabet:   count = 0   for ch in lis:    if ch == c:     count+=1   li.append(count/len(lis))  return li   def textToList(text,length): # 根据密钥长度将密文分组  textMatrix = []  row = []  index = 0  for ch in text:   row.append(ch)   index += 1   if index % length ==0:    textMatrix.append(row)    row = []  return textMatrix   if __name__ == '__main__':  cipherText = openfile(r'') # 这里要根据文档目录的不同而改变  plainText= virginiaCrack(cipherText)  print('the plainText:\n',plainText)

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持开心学习网。

原文链接：https://blog.csdn.net/Aslani/article/details/53729804