凯撒加密【加密+暴力破解+文本单词匹配】

要求：

1 实现指定秘钥的凯撒密码加密

2 已知秘钥解密

3 未知秘钥，采用暴力破解

4 对破解出的密码，与单词词典比对，找出明文的那一条，得到加密的秘钥

 

采用python实现

报告+代码链接

链接：https://pan.baidu.com/s/1aOIhnLFIy36Y05AnrCz8pw
提取码：zulz

Caesar_encryption.py

MAX_KEY_SIZE = 26

def getMode():
    while True:
        print('请选择加密或解密模式,或者选择暴力破解：')
        print('加密:encrypt(e)')
        print('解密:decrypt(d)')
        print('暴力破解:brute(b)')
        mode = input().lower()
        if mode in 'encrypt e decrypt d brute b'.split():
            return mode
        else:
            print('请输入"encrypt"或"e"或"decrypt"或"d"或"brute"或"b"!')

def getMessage():
    print('请输入你的信息：')
    return input()

def getKey():
    key = 0
    while True:
        print('请输入密钥数字(1-25)')
        key = int(input())
        if (key >=1 and key <= MAX_KEY_SIZE):
            return key

def getTranslatedMessage(mode, message, key):
    if mode[0] == 'd':
        key = -key   #如果是解密的 就反过来
    translated = ''
    for symbol in message:
        if symbol.isalpha(): #是否都是字母
            num = ord(symbol) #得到字符symbol对应的ASCII码
            num += key  #解密出对应的ASCII码
            if symbol.isupper():
                if num > ord('Z'):
                    num -= 26
                elif num < ord('A'):
                    num += 26
            elif symbol.islower():
                if num > ord('z'):
                    num -= 26
                elif num < ord('a'):
                    num += 26

            translated += chr(num)  #与ord对应  将码转字符
        else:
            translated += symbol  #不是字母的位置就直接添加了

    write_file(translated,"cipher.txt")
    return translated

def write_file(str,filename):
    with open(filename,'w') as fp:
        fp.write(str)



mode = getMode()
message = getMessage()

if mode[0] != 'b':
    key = getKey()

print('你要翻译的信息是:')
if mode[0] != 'b':
    print(getTranslatedMessage(mode, message, key))
else:
    for key in range(1, MAX_KEY_SIZE + 1):
        print(key, getTranslatedMessage('decrypt', message, key))

　　

Caesar_ Decrypt.py

########################功能#######################
#1、文件读入4万个常用单词、密文
#2、解密后存文件
#3、cipher 是存的原始密文  cipher_no 是把原始密文的标点符号过滤后的密文
########################程序###########################
import time
#存放100常用单词的文本
WORDS_FILE_NAME = 'diction.txt'
#WORDS_FILE_NAME = 'words.txt'
#加密所用的对照表
KEY_FILE_NAME = 'duizhao.txt'
#存放密文的文本
CIPHER_FILE_NAME = 'cipher.txt'
#存放明文的文本
PLAIN_FILE_NAME = 'plain.txt'

letters = 'abcdefghijklmnopqrstuvwxyz'

#读入一个文本
def read_file(filename):
    lines = ''
    with open(filename,'r') as fp:
        for line in fp:
            lines += line
    return lines

#写入字符串到文本
def write_file(str,filename):
    with open(filename,'w') as fp:
        fp.write(str)

#根据秘钥加密
def encrypt(key,textFileString):
    lines = ''
    #读入待加密文本
    lines = read_file(textFileString)
    lines.lower()
    #读入对应转换表
    letters1 = '' #选择对应的转换表
    with open(KEY_FILE_NAME, 'r') as fp1:
        for line in fp1:
            key -= 1
            if key == -1:  #找到key那一行
                letters1 += line

    #进行加密
    cstring = ''
    length = len(lines)
    for i in range(0, length):
        if lines[i] >= 'a' and lines[i] <= 'z':
            for j in range(0, 26):
                if lines[i] == letters[j]:  #letters = 'abcdefghijklmnopqrstuvwxyz'
                    cstring += letters1[j]  #进行相应位的替换
        else:
            cstring += lines[i]
    return cstring


#根据指定的秘钥解密
def decipher1(key,textFileString):
    #从文件读入数据
    lines = ''
    cstring = ''#密文结果
    lines = read_file(textFileString)
    #全部转换为小写字母
    lines.lower()
    #根据key进行解密
    letters1 = ''
    with open(KEY_FILE_NAME,'r') as fp1:
        for line in fp1:
            key += 1
            if key == 27:
                letters1+=line
    #开始解密
    length  = len(lines)
    for i in range(0,length):
        if lines[i]>='a' and lines[i] <= 'z':
            for j in range(0, 26):
                if lines[i] == letters[j]:
                    cstring+=letters1[j]
        else:
            cstring += lines[i]
    return cstring

#根据常用词汇表解密
def decipher2(textFileString):
    #读入一百个单词
    words = read_file(WORDS_FILE_NAME).split('
')  #读取文件所有内容 并以回车分词
    max = 0;
    index = 0;
    #暴力破解选择一个秘钥
    filename_no = read_file(textFileString).replace(',','')
    filename_no = filename_no.replace('.','')
    filename_no = filename_no.replace(':','')
    filename_no = filename_no.replace('"','')
    filename_no = filename_no.replace('?','')
    write_file(filename_no,'cipher_no.txt')  #符号替换完 存入_no
    print("暴力破解的所有结果：")
    for i in range(1,26):
        pstring = decipher1(i,'cipher_no.txt')
        print("秘钥为%d"%i,"时，解密的结果：",pstring)
        plainWords = pstring.split(' ')
        #对比
        length = len(plainWords)
        temp = 0
        for j in range(0,length):
            if plainWords[j] in words:
                temp += 1  # 在词库里面的词语数量
        if temp > max:
            max = temp
            index = i

    print("经过词典比对，最终得出正确的明文：")
    print('破解秘钥是%d'%index)
    # print('单词个数%d',length)
    print('单词的匹配程度{}%'.format(float('%.2f'%(max*100/length))))
    #写入文件
    str = decipher1(index,textFileString)
    write_file(str,PLAIN_FILE_NAME)
    return decipher1(index,textFileString)

def main():
    print('主程序入口')
    start_time = time.time()
    print('解密后的结果:
'+decipher2('cipher.txt'))  #解密
    #print('加密后的结果:
'+encrypt(3, 'D:\2018Python_Learningpythonlearning\plain.txt')) #加密
    end_time = time.time()
    run_time = end_time-start_time
    print('程序的运行时间为:{}'.format(run_time))

if __name__ == '__main__':
    main()

　　有一些txt见网盘链接