技術標籤：python密碼學

這個學期學習了密碼學，在老師的指導下實現了des資料加密程式碼如下，等有空了再補說明

class des(object):
    """DES加密器
    該類可實現字串的加密與解密
    """

    # 初始化函式
    def __init__(self):
        """初始化方法
        函式有：
        private(非必要請勿使用)：
        1.移位函式_Shift(self,s, n)
        2.異或函式_Xor(self,a, b)
        3.明文字串轉二進位制_Get_Bin(self,Texts)
        4.密文字串轉二進位制_Get_bin(self,Texts)
        5.二進位制轉字元函式_Bin_Str(self,s)
        6.十進位制轉二進位制_Ten_To_Two(self,n)
        7.PC置換_PC(self,s, flag)
        8.金鑰生成器_Get_Sk(self)
        9.獲取明文字串_Get_Plaintext(self)
        10.獲取密文字串_Get_Ciphertext(self)
        11.s盒中取數函式_Get_S(self,h, l, n)
        12.P置換_Exchange_P(self,A)
        13.f函式_Function(self,R, K)
        14.IP置換_Exchange_IP(self,s, n)
        public：
        15.加密函式Encryption(self)
        16.解密函式Dencryption(self)
        17.以數字形式展示ShowC_in_num(self,n)
        18.明文以文字形式展示Show_Text(self,flag)
        19.密文以文字形式展示Show_text(self,flag)
        變數：
        1.金鑰self.__Key
        2.明文self.__Plaintext
        3.密文self.__Ciphertext
        """
 


    # 移位函式
    def shift(self, s, n):
        '''s:需要移位的字串
           n:需要移動的位數
        '''
        return s[n:] + s[:n]

    # 異或函式
    def xor(self, a, b):
        """異或函式
        a,b:等長的字串
        return：a和b異或後的結果
        """
        t = zip(a, b)
        s = [(int
 
(i) + int(j)) % 2 for i, j in t]
        S = ''
        for i in s:
            S = S + str(i)
        return S

    # 明文字串轉二進位制
    def get_p_bin(self, Texts):
        """字串轉二進位制
        Text：字串
        return 字串對應的二進位制的編碼
        """
        Text_bin = ''
        for text in
 
 Texts:
            s = ord(text)
            s_bin = '{:016b}'.format(s)
            Text_bin = Text_bin + s_bin
        return Text_bin

    # 密文字串轉二進位制
    def get_c_bin(self, Texts):
        """字串轉二進位制
        Text：字串
        return 字串對應的二進位制的編碼
        """
        Text_bin = ''
        for text in Texts:
            s = ord(text)
            s_bin = '{:08b}'.format(s)
            Text_bin = Text_bin + s_bin
        return Text_bin

    # 二進位制轉字元函式
    def bin_str(self, s):
        '''獲取16位的01串，返回對應的漢字'''
        try:
            return chr(int(s, 2))
        except:
            return -1

    # 十進位制轉二進位制
    def ten_to_two(self, n):
        """返回小於16的數轉換為四位二進位制數(字串)
            n:小於16的十進位制數
            return：四位的二進位制數，不足四位在前方補零
        """
        n2 = bin(n)[2:]
        num = len(bin(n)[2:])
        if num >= 4: return n2
        for i in range(4 - num):
            n2 = '0' + n2
        return n2

    # PC置換
    def pc(self, s, flag):
        PC1 = [57, 49, 41, 33, 25, 17, 9, \
               1, 58, 50, 42, 34, 26, 18, \
               10, 2, 59, 51, 43, 35, 27, \
               19, 11, 3, 60, 52, 44, 36, \
               63, 55, 47, 39, 31, 23, 15, \
               7, 62, 54, 46, 38, 30, 22, \
               14, 6, 61, 53, 45, 37, 29, \
               21, 13, 5, 28, 20, 12, 4]
        PC2 = [14, 17, 11, 24, 1, 5, 3, 28, \
               15, 6, 21, 10, 23, 19, 12, 4, \
               26, 8, 16, 7, 27, 20, 13, 2, \
               41, 52, 31, 37, 47, 55, 30, 40, \
               51, 45, 33, 48, 44, 49, 39, 56, \
               34, 53, 46, 42, 50, 36, 29, 32]
        S = ''
        if flag == 1:
            for i in PC1:
                S = S + s[i - 1]
        if flag == 2:
            for i in PC2:
                S = S + s[i - 1]
        return S

    # 金鑰生成器
    def get_sk(self, text):  # 獲取金鑰
        shift_num = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1]
        k = text
        # 請輸入金鑰（四個漢字）
        k_bin = self.get_p_bin(k)
        k_bin = self.pc(k_bin, 1)  # PC_1置換
        K = []
        # print('k_bin=',k_bin)
        num = 0
        for i in range(16):
            num = num + 1
            k_bin = self.shift(k_bin[:28], shift_num[i]) + self.shift(k_bin[28:], shift_num[i])  # 分組移位
            K.append(self.pc(k_bin, 2))  # PC_2置換，並記錄
            if num >= 4:
                continue
        self.__key = K


    # 獲取明文字串
    def get_plaintext(self, text):
        """獲取需要加密的明文並換成二進位制形式"""
        m = text
        m_bin = []
        M = self.get_p_bin(m)
        flag = 0
        i = 0
        for i in range(int(len(M) / 64)):  # 四字一組
            m_bin.append(M[64 * i:64 * (1 + i)])
            flag = 1
        i = i
        if len(M) > 64:
            m_bin.append(M[64 * (1 + i):] + (64 - len(M[64 * (1 + i):])) * '0')  # 字多於於四個時，末位不足四位
        elif len(M) < 64:
            m_bin.append(M + (64 - len(M)) * '0')  # 字少於四個時
        return m_bin  # 返回二進位制程式碼列表

    # 獲取密文字串
    def get_ciphertext(self, text, flag):
        m = text
        m_bin = []
        M = ''
        if flag == 0:
            M = self.get_c_bin(m)
        elif flag == 2:
            for i in text.split(' ')[:-1]:
                if len(i) < 8:
                    M = M + '0' * (16 - len(i)) + i
                else:
                    M = M + i
        elif flag == 16:
            for i in text.split(' ')[:-1]:
                if len(bin(int(i, 16))[2:]) < 8:
                    M = M + '0' * (8 - len(bin(int(i, 16))[2:])) + bin(int(i, 16))[2:]
                else:
                    M = M + bin(int(i, 16))[2:]
        flag = 0
        for i in range(int(len(M) / 64)):  # 四字一組
            m_bin.append(M[64 * i:64 * (1 + i)])
            flag = 1
        if len(M) % 64 > 0:
            m_bin.append(M[64 * (1 + i):] + (64 - len(M[64 * (1 + i):])) * '0')  # 字多於於四個時，末位不足四位
        elif flag == 0:
            m_bin.append(M + (64 - len(M)) * '0')  # 字少於四個時
        return m_bin  # 返回二進位制程式碼列表flag

    # s盒中取數函式
    def get_s(self, h, l, n):
        '''獲取s盒中的數
        h：行
        l：列
        n：第n+1個盒
        返回指定s盒的第h行第j列的數
        '''
        s1 = [14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, \
              0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, \
              4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, \
              15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]
        s2 = [15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, \
              3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, \
              0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, \
              13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9]
        s3 = [10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, \
              13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, \
              13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, \
              1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12]
        s4 = [7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, \
              13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, \
              10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, \
              3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14]
        s5 = [2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, \
              14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, \
              4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, \
              11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3]
        s6 = [12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, \
              10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, \
              9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, \
              4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13]
        s7 = [4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, \
              13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, \
              1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, \
              6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12]
        s8 = [13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, \
              1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, \
              7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, \
              2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11]
        if n == 0:
            return s1[h * 16 + l]
        if n == 1:
            return s2[h * 16 + l]
        if n == 2:
            return s3[h * 16 + l]
        if n == 3:
            return s4[h * 16 + l]
        if n == 4:
            return s5[h * 16 + l]
        if n == 5:
            return s6[h * 16 + l]
        if n == 6:
            return s7[h * 16 + l]
        if n == 7:
            return s8[h * 16 + l]

    # P置換
    def exchange_p(self, a):
        """對得到的資料進行P置換
            A：需要進行P置換的字串
            return 進行P置換後的字串
        """
        p = [16, 7, 20, 21, 29, 12, 28, 17, \
             1, 15, 23, 26, 5, 18, 31, 10, \
             2, 8, 24, 14, 32, 27, 3, 9, \
             19, 13, 30, 6, 22, 11, 4, 25]
        f = ''
        for i in p:
            f = f + a[i - 1]
        return f

    # f函式
    def function(self, r, k):
        """f函式"""
        # 擴張函式
        e = [32, 1, 2, 3, 4, 5, \
             4, 5, 6, 7, 8, 9, \
             8, 9, 10, 11, 12, 13, \
             12, 13, 14, 15, 16, 17, \
             16, 17, 18, 19, 20, 21, \
             20, 21, 22, 23, 24, 25, \
             24, 25, 26, 27, 28, 29, \
             28, 29, 30, 31, 32, 1]
        r_e = ''  # 初始化擴張後R
        for i in e:
            r_e = r_e + r[i - 1]
        s = self.xor(r_e, k)
        # 通過s盒進行壓縮
        f = ''
        for i in range(8):
            h = int(s[0 + 6 * i]) * 2 + int(s[5 + 6 * i])  # 行
            l = int(s[1 + 6 * i]) * 8 + int(s[2 + 6 * i]) * 4 + int(s[3 + 6 * i]) * 2 + int(s[4 + 6 * i])  # 列
            f = f + self.ten_to_two(self.get_s(h, l, i))
        # 置換P
        f_p = self.exchange_p(f)
        return f_p

    # IP置換
    def exchange_ip(self, s, n):
        """IP置換
        S:需要置換的字串
        n：置換引數，0為初始置換，1為逆初始置換
        return ：進行置換後的字串
        """
        ip = [58, 50, 42, 34, 26, 18, 10, 2, \
              60, 52, 44, 36, 28, 20, 12, 4, \
              62, 54, 46, 38, 30, 22, 14, 6, \
              64, 56, 48, 40, 32, 24, 16, 8, \
              57, 49, 41, 33, 25, 17, 9, 1, \
              59, 51, 43, 35, 27, 19, 11, 3, \
              61, 53, 45, 37, 29, 21, 13, 5, \
              63, 55, 47, 39, 31, 23, 15, 7]

        ip_ = [40, 8, 48, 16, 56, 24, 64, 32, \
               39, 7, 47, 15, 55, 23, 63, 31, \
               38, 6, 46, 14, 54, 22, 62, 30, \
               37, 5, 45, 13, 53, 21, 61, 29, \
               36, 4, 44, 12, 52, 20, 60, 28, \
               35, 3, 43, 11, 51, 19, 59, 27, \
               34, 2, 42, 10, 50, 18, 58, 26, \
               33, 1, 41, 9, 49, 17, 57, 25]
        S = ''
        if n == 0:
            for i in ip:
                S = S + s[i - 1]
        if n == 1:
            for i in ip_:
                S = S + s[i - 1]
        return S

    # 加密函式
    def encryption(self, text):
        key = self.__key
        c = []  # 密文
        self.__plaintext = self.get_plaintext(text)
        for m in self.__plaintext:
            m = self.exchange_ip(m, 0)  # ip置換
            L = m[:32]
            R = m[32:]
            for j in range(16):  # 16輪迭代
                T = L
                L = R
                R = self.xor(T, self.function(R, key[j]))
            c.append(self.exchange_ip(R + L, 1))
        self.__ciphertext = c
        return c

    # 解密函式
    def dencryption(self, text, flag):
        """"flag=0為字串，flag=2為二進位制串，flag=16為十六進位制"""
        key = self.__key
        M = []  # 譯文容器
        self.__ciphertext = self.get_ciphertext(text, flag)
        for m in self.__ciphertext:
            m = self.exchange_ip(m, 0)  # ip置換
            L = m[:32]
            R = m[32:]
            for j in range(16):  # 16輪迭代
                T = L
                L = R
                R = self.xor(T, self.function(R, key[15 - j]))
            M.append(self.exchange_ip(R + L, 1))
        self.__plaintext = M
        return M

    # 以數字形式展示
    def showc_in_num(self, n):
        ''''n代表進位制，目前僅支援2進位制和16進位制'''
        cstr = ''
        s_hex = ''
        for i in self.__ciphertext:
            cstr = cstr + i
        if n == 2:
            for i in range(int(len(cstr) / 8)):
                s_hex = s_hex + cstr[8 * i:8 + 8 * i] + ' '
            return s_hex
        elif n == 16:
            s_hex = ''
            for i in range(int(len(cstr) / 8)):
                s_hex = s_hex + str(hex(int(cstr[8 * i:8 + 8 * i], 2))) + ' '
            return s_hex
        else:
            return '請期待後續版本，感謝您的信賴'

    # 明文以文字形式展示
    def show_mtext(self):
        '''明文'''
        M = self.__plaintext
        m_text = ''
        for text in M:
            for i in range(4):
                if text[i * 16:16 * (1 + i)] != '0' * 16:
                    m_text = m_text + self.bin_str(text[i * 16:16 * (1 + i)])
        return m_text

    # 密文以文字形式展示
    def show_ctext(self):
        '''密文'''
        M = self.__ciphertext
        m_text = ''
        for text in M:
            for i in range(8):
                m_text = m_text + self.bin_str(text[i * 8:8 * (1 + i)])
        return m_text


if __name__ == '__main__':
    key = '塞德里克'
    D = des()
    D.get_sk(key)
    text = '面朝大海，春暖花開！'
    D.encryption(text)
    c = D.show_ctext()
    print('密文：',c)
    D.dencryption(c,0)
    m = D.show_mtext()
    print('明文：',m)

結果