[Python]实现DES加密算法和3DES加密算法

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pyDes.py

##############################################################################                 Documentation                    ############################################################################### Author:   Todd Whiteman# Date:     16th March, 2009# Verion:   2.0.0# License:  Public Domain - free to do as you wish# Homepage: http://twhiteman.netfirms.com/des.html## This is a pure python implementation of the DES encryption algorithm.# It's pure python to avoid portability issues, since most DES # implementations are programmed in C (for performance reasons).## Triple DES class is also implemented, utilising the DES base. Triple DES# is either DES-EDE3 with a 24 byte key, or DES-EDE2 with a 16 byte key.## See the README.txt that should come with this python module for the# implementation methods used.## Thanks to:#  * David Broadwell for ideas, comments and suggestions.#  * Mario Wolff for pointing out and debugging some triple des CBC errors.#  * Santiago Palladino for providing the PKCS5 padding technique.#  * Shaya for correcting the PAD_PKCS5 triple des CBC errors.#"""A pure python implementation of the DES and TRIPLE DES encryption algorithms.Class initialization--------------------pyDes.des(key, [mode], [IV], [pad], [padmode])pyDes.triple_des(key, [mode], [IV], [pad], [padmode])key     -> Bytes containing the encryption key. 8 bytes for DES, 16 or 24 bytes       for Triple DESmode    -> Optional argument for encryption type, can be either       pyDes.ECB (Electronic Code Book) or pyDes.CBC (Cypher Block Chaining)IV      -> Optional Initial Value bytes, must be supplied if using CBC mode.       Length must be 8 bytes.pad     -> Optional argument, set the pad character (PAD_NORMAL) to use during       all encrypt/decrpt operations done with this instance.padmode -> Optional argument, set the padding mode (PAD_NORMAL or PAD_PKCS5)       to use during all encrypt/decrpt operations done with this instance.I recommend to use PAD_PKCS5 padding, as then you never need to worry about anypadding issues, as the padding can be removed unambiguously upon decryptingdata that was encrypted using PAD_PKCS5 padmode.Common methods--------------encrypt(data, [pad], [padmode])decrypt(data, [pad], [padmode])data    -> Bytes to be encrypted/decryptedpad     -> Optional argument. Only when using padmode of PAD_NORMAL. For       encryption, adds this characters to the end of the data block when       data is not a multiple of 8 bytes. For decryption, will remove the       trailing characters that match this pad character from the last 8       bytes of the unencrypted data block.padmode -> Optional argument, set the padding mode, must be one of PAD_NORMAL       or PAD_PKCS5). Defaults to PAD_NORMAL.      Example-------from pyDes import *data = "Please encrypt my data"k = des("DESCRYPT", CBC, "\0\0\0\0\0\0\0\0", pad=None, padmode=PAD_PKCS5)# For Python3, you'll need to use bytes, i.e.:#   data = b"Please encrypt my data"#   k = des(b"DESCRYPT", CBC, b"\0\0\0\0\0\0\0\0", pad=None, padmode=PAD_PKCS5)d = k.encrypt(data)print "Encrypted: %r" % dprint "Decrypted: %r" % k.decrypt(d)assert k.decrypt(d, padmode=PAD_PKCS5) == dataSee the module source (pyDes.py) for more examples of use.You can also run the pyDes.py file without and arguments to see a simple test.Note: This code was not written for high-end systems needing a fast      implementation, but rather a handy portable solution with small usage."""import sys# _pythonMajorVersion is used to handle Python2 and Python3 differences._pythonMajorVersion = sys.version_info[0]# Modes of crypting / cypheringECB =    0CBC =    1# Modes of paddingPAD_NORMAL = 1PAD_PKCS5 = 2# PAD_PKCS5: is a method that will unambiguously remove all padding#            characters after decryption, when originally encrypted with#            this padding mode.# For a good description of the PKCS5 padding technique, see:# http://www.faqs.org/rfcs/rfc1423.html# The base class shared by des and triple des.class _baseDes(object):    def __init__(self, mode=ECB, IV=None, pad=None, padmode=PAD_NORMAL):        if IV:            IV = self._guardAgainstUnicode(IV)        if pad:            pad = self._guardAgainstUnicode(pad)        self.block_size = 8        # Sanity checking of arguments.        if pad and padmode == PAD_PKCS5:            raise ValueError("Cannot use a pad character with PAD_PKCS5")        if IV and len(IV) != self.block_size:            raise ValueError("Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")        # Set the passed in variables        self._mode = mode        self._iv = IV        self._padding = pad        self._padmode = padmode    def getKey(self):        """getKey() -> bytes"""        return self.__key    def setKey(self, key):        """Will set the crypting key for this object."""        key = self._guardAgainstUnicode(key)        self.__key = key    def getMode(self):        """getMode() -> pyDes.ECB or pyDes.CBC"""        return self._mode    def setMode(self, mode):        """Sets the type of crypting mode, pyDes.ECB or pyDes.CBC"""        self._mode = mode    def getPadding(self):        """getPadding() -> bytes of length 1. Padding character."""        return self._padding    def setPadding(self, pad):        """setPadding() -> bytes of length 1. Padding character."""        if pad is not None:            pad = self._guardAgainstUnicode(pad)        self._padding = pad    def getPadMode(self):        """getPadMode() -> pyDes.PAD_NORMAL or pyDes.PAD_PKCS5"""        return self._padmode            def setPadMode(self, mode):        """Sets the type of padding mode, pyDes.PAD_NORMAL or pyDes.PAD_PKCS5"""        self._padmode = mode    def getIV(self):        """getIV() -> bytes"""        return self._iv    def setIV(self, IV):        """Will set the Initial Value, used in conjunction with CBC mode"""        if not IV or len(IV) != self.block_size:            raise ValueError("Invalid Initial Value (IV), must be a multiple of " + str(self.block_size) + " bytes")        IV = self._guardAgainstUnicode(IV)        self._iv = IV    def _padData(self, data, pad, padmode):        # Pad data depending on the mode        if padmode is None:            # Get the default padding mode.            padmode = self.getPadMode()        if pad and padmode == PAD_PKCS5:            raise ValueError("Cannot use a pad character with PAD_PKCS5")        if padmode == PAD_NORMAL:            if len(data) % self.block_size == 0:                # No padding required.                return data            if not pad:                # Get the default padding.                pad = self.getPadding()            if not pad:                raise ValueError("Data must be a multiple of " + str(self.block_size) + " bytes in length. Use padmode=PAD_PKCS5 or set the pad character.")            data += (self.block_size - (len(data) % self.block_size)) * pad                elif padmode == PAD_PKCS5:            pad_len = 8 - (len(data) % self.block_size)            if _pythonMajorVersion < 3:                data += pad_len * chr(pad_len)            else:                data += bytes([pad_len] * pad_len)        return data    def _unpadData(self, data, pad, padmode):        # Unpad data depending on the mode.        if not data:            return data        if pad and padmode == PAD_PKCS5:            raise ValueError("Cannot use a pad character with PAD_PKCS5")        if padmode is None:            # Get the default padding mode.            padmode = self.getPadMode()        if padmode == PAD_NORMAL:            if not pad:                # Get the default padding.                pad = self.getPadding()            if pad:                data = data[:-self.block_size] + \                       data[-self.block_size:].rstrip(pad)        elif padmode == PAD_PKCS5:            if _pythonMajorVersion < 3:                pad_len = ord(data[-1])            else:                pad_len = data[-1]            data = data[:-pad_len]        return data    def _guardAgainstUnicode(self, data):        # Only accept byte strings or ascii unicode values, otherwise        # there is no way to correctly decode the data into bytes.        if _pythonMajorVersion < 3:            if isinstance(data, unicode):                raise ValueError("pyDes can only work with bytes, not Unicode strings.")        else:            if isinstance(data, str):                # Only accept ascii unicode values.                try:                    return data.encode('ascii')                except UnicodeEncodeError:                    pass                raise ValueError("pyDes can only work with encoded strings, not Unicode.")        return data##############################################################################                     DES                        ##############################################################################class des(_baseDes):    """DES encryption/decrytpion class    Supports ECB (Electronic Code Book) and CBC (Cypher Block Chaining) modes.    pyDes.des(key,[mode], [IV])    key  -> Bytes containing the encryption key, must be exactly 8 bytes    mode -> Optional argument for encryption type, can be either pyDes.ECB        (Electronic Code Book), pyDes.CBC (Cypher Block Chaining)    IV   -> Optional Initial Value bytes, must be supplied if using CBC mode.        Must be 8 bytes in length.    pad  -> Optional argument, set the pad character (PAD_NORMAL) to use        during all encrypt/decrpt operations done with this instance.    padmode -> Optional argument, set the padding mode (PAD_NORMAL or        PAD_PKCS5) to use during all encrypt/decrpt operations done        with this instance.    """    # Permutation and translation tables for DES    __pc1 = [56, 48, 40, 32, 24, 16,  8,          0, 57, 49, 41, 33, 25, 17,          9,  1, 58, 50, 42, 34, 26,         18, 10,  2, 59, 51, 43, 35,         62, 54, 46, 38, 30, 22, 14,          6, 61, 53, 45, 37, 29, 21,         13,  5, 60, 52, 44, 36, 28,         20, 12,  4, 27, 19, 11,  3    ]    # number left rotations of pc1    __left_rotations = [        1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1    ]    # permuted choice key (table 2)    __pc2 = [        13, 16, 10, 23,  0,  4,         2, 27, 14,  5, 20,  9,        22, 18, 11,  3, 25,  7,        15,  6, 26, 19, 12,  1,        40, 51, 30, 36, 46, 54,        29, 39, 50, 44, 32, 47,        43, 48, 38, 55, 33, 52,        45, 41, 49, 35, 28, 31    ]    # initial permutation IP    __ip = [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,        56, 48, 40, 32, 24, 16, 8,  0,        58, 50, 42, 34, 26, 18, 10, 2,        60, 52, 44, 36, 28, 20, 12, 4,        62, 54, 46, 38, 30, 22, 14, 6    ]    # Expansion table for turning 32 bit blocks into 48 bits    __expansion_table = [        31,  0,  1,  2,  3,  4,         3,  4,  5,  6,  7,  8,         7,  8,  9, 10, 11, 12,        11, 12, 13, 14, 15, 16,        15, 16, 17, 18, 19, 20,        19, 20, 21, 22, 23, 24,        23, 24, 25, 26, 27, 28,        27, 28, 29, 30, 31,  0    ]    # The (in)famous S-boxes    __sbox = [        # 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],    ]    # 32-bit permutation function P used on the output of the S-boxes    __p = [        15, 6, 19, 20, 28, 11,        27, 16, 0, 14, 22, 25,        4, 17, 30, 9, 1, 7,        23,13, 31, 26, 2, 8,        18, 12, 29, 5, 21, 10,        3, 24    ]    # final permutation IP^-1    __fp = [        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,        32,  0, 40,  8, 48, 16, 56, 24    ]    # Type of crypting being done    ENCRYPT =    0x00    DECRYPT =    0x01    # Initialisation    def __init__(self, key, mode=ECB, IV=None, pad=None, padmode=PAD_NORMAL):        # Sanity checking of arguments.        if len(key) != 8:            raise ValueError("Invalid DES key size. Key must be exactly 8 bytes long.")        _baseDes.__init__(self, mode, IV, pad, padmode)        self.key_size = 8        self.L = []        self.R = []        self.Kn = [ [0] * 48 ] * 16    # 16 48-bit keys (K1 - K16)        self.final = []        self.setKey(key)    def setKey(self, key):        """Will set the crypting key for this object. Must be 8 bytes."""        _baseDes.setKey(self, key)        self.__create_sub_keys()    def __String_to_BitList(self, data):        """Turn the string data, into a list of bits (1, 0)'s"""        if _pythonMajorVersion < 3:            # Turn the strings into integers. Python 3 uses a bytes            # class, which already has this behaviour.            data = [ord(c) for c in data]        l = len(data) * 8        result = [0] * l        pos = 0        for ch in data:            i = 7            while i >= 0:                if ch & (1 << i) != 0:                    result[pos] = 1                else:                    result[pos] = 0                pos += 1                i -= 1        return result    def __BitList_to_String(self, data):        """Turn the list of bits -> data, into a string"""        result = []        pos = 0        c = 0        while pos < len(data):            c += data[pos] << (7 - (pos % 8))            if (pos % 8) == 7:                result.append(c)                c = 0            pos += 1        if _pythonMajorVersion < 3:            return ''.join([ chr(c) for c in result ])        else:            return bytes(result)    def __permutate(self, table, block):        """Permutate this block with the specified table"""        return list(map(lambda x: block[x], table))        # Transform the secret key, so that it is ready for data processing    # Create the 16 subkeys, K[1] - K[16]    def __create_sub_keys(self):        """Create the 16 subkeys K[1] to K[16] from the given key"""        key = self.__permutate(des.__pc1, self.__String_to_BitList(self.getKey()))        i = 0        # Split into Left and Right sections        self.L = key[:28]        self.R = key[28:]        while i < 16:            j = 0            # Perform circular left shifts            while j < des.__left_rotations[i]:                self.L.append(self.L[0])                del self.L[0]                self.R.append(self.R[0])                del self.R[0]                j += 1            # Create one of the 16 subkeys through pc2 permutation            self.Kn[i] = self.__permutate(des.__pc2, self.L + self.R)            i += 1    # Main part of the encryption algorithm, the number cruncher :)    def __des_crypt(self, block, crypt_type):        """Crypt the block of data through DES bit-manipulation"""        block = self.__permutate(des.__ip, block)        self.L = block[:32]        self.R = block[32:]        # Encryption starts from Kn[1] through to Kn[16]        if crypt_type == des.ENCRYPT:            iteration = 0            iteration_adjustment = 1        # Decryption starts from Kn[16] down to Kn[1]        else:            iteration = 15            iteration_adjustment = -1        i = 0        while i < 16:            # Make a copy of R[i-1], this will later become L[i]            tempR = self.R[:]            # Permutate R[i - 1] to start creating R[i]            self.R = self.__permutate(des.__expansion_table, self.R)            # Exclusive or R[i - 1] with K[i], create B[1] to B[8] whilst here            self.R = list(map(lambda x, y: x ^ y, self.R, self.Kn[iteration]))            B = [self.R[:6], self.R[6:12], self.R[12:18], self.R[18:24], self.R[24:30], self.R[30:36], self.R[36:42], self.R[42:]]            # Optimization: Replaced below commented code with above            #j = 0            #B = []            #while j < len(self.R):            #    self.R[j] = self.R[j] ^ self.Kn[iteration][j]            #    j += 1            #    if j % 6 == 0:            #        B.append(self.R[j-6:j])            # Permutate B[1] to B[8] using the S-Boxes            j = 0            Bn = [0] * 32            pos = 0            while j < 8:                # Work out the offsets                m = (B[j][0] << 1) + B[j][5]                n = (B[j][1] << 3) + (B[j][2] << 2) + (B[j][3] << 1) + B[j][4]                # Find the permutation value                v = des.__sbox[j][(m << 4) + n]                # Turn value into bits, add it to result: Bn                Bn[pos] = (v & 8) >> 3                Bn[pos + 1] = (v & 4) >> 2                Bn[pos + 2] = (v & 2) >> 1                Bn[pos + 3] = v & 1                pos += 4                j += 1            # Permutate the concatination of B[1] to B[8] (Bn)            self.R = self.__permutate(des.__p, Bn)            # Xor with L[i - 1]            self.R = list(map(lambda x, y: x ^ y, self.R, self.L))            # Optimization: This now replaces the below commented code            #j = 0            #while j < len(self.R):            #    self.R[j] = self.R[j] ^ self.L[j]            #    j += 1            # L[i] becomes R[i - 1]            self.L = tempR            i += 1            iteration += iteration_adjustment                # Final permutation of R[16]L[16]        self.final = self.__permutate(des.__fp, self.R + self.L)        return self.final    # Data to be encrypted/decrypted    def crypt(self, data, crypt_type):        """Crypt the data in blocks, running it through des_crypt()"""        # Error check the data        if not data:            return ''        if len(data) % self.block_size != 0:            if crypt_type == des.DECRYPT: # Decryption must work on 8 byte blocks                raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n.")            if not self.getPadding():                raise ValueError("Invalid data length, data must be a multiple of " + str(self.block_size) + " bytes\n. Try setting the optional padding character")            else:                data += (self.block_size - (len(data) % self.block_size)) * self.getPadding()            # print "Len of data: %f" % (len(data) / self.block_size)        if self.getMode() == CBC:            if self.getIV():                iv = self.__String_to_BitList(self.getIV())            else:                raise ValueError("For CBC mode, you must supply the Initial Value (IV) for ciphering")        # Split the data into blocks, crypting each one seperately        i = 0        dict = {}        result = []        #cached = 0        #lines = 0        while i < len(data):            # Test code for caching encryption results            #lines += 1            #if dict.has_key(data[i:i+8]):                #print "Cached result for: %s" % data[i:i+8]            #    cached += 1            #    result.append(dict[data[i:i+8]])            #    i += 8            #    continue                            block = self.__String_to_BitList(data[i:i+8])            # Xor with IV if using CBC mode            if self.getMode() == CBC:                if crypt_type == des.ENCRYPT:                    block = list(map(lambda x, y: x ^ y, block, iv))                    #j = 0                    #while j < len(block):                    #    block[j] = block[j] ^ iv[j]                    #    j += 1                processed_block = self.__des_crypt(block, crypt_type)                if crypt_type == des.DECRYPT:                    processed_block = list(map(lambda x, y: x ^ y, processed_block, iv))                    #j = 0                    #while j < len(processed_block):                    #    processed_block[j] = processed_block[j] ^ iv[j]                    #    j += 1                    iv = block                else:                    iv = processed_block            else:                processed_block = self.__des_crypt(block, crypt_type)            # Add the resulting crypted block to our list            #d = self.__BitList_to_String(processed_block)            #result.append(d)            result.append(self.__BitList_to_String(processed_block))            #dict[data[i:i+8]] = d            i += 8        # print "Lines: %d, cached: %d" % (lines, cached)        # Return the full crypted string        if _pythonMajorVersion < 3:            return ''.join(result)        else:            return bytes.fromhex('').join(result)    def encrypt(self, data, pad=None, padmode=None):        """encrypt(data, [pad], [padmode]) -> bytes        data : Bytes to be encrypted        pad  : Optional argument for encryption padding. Must only be one byte        padmode : Optional argument for overriding the padding mode.        The data must be a multiple of 8 bytes and will be encrypted        with the already specified key. Data does not have to be a        multiple of 8 bytes if the padding character is supplied, or        the padmode is set to PAD_PKCS5, as bytes will then added to        ensure the be padded data is a multiple of 8 bytes.        """        data = self._guardAgainstUnicode(data)        if pad is not None:            pad = self._guardAgainstUnicode(pad)        data = self._padData(data, pad, padmode)        return self.crypt(data, des.ENCRYPT)    def decrypt(self, data, pad=None, padmode=None):        """decrypt(data, [pad], [padmode]) -> bytes        data : Bytes to be encrypted        pad  : Optional argument for decryption padding. Must only be one byte        padmode : Optional argument for overriding the padding mode.        The data must be a multiple of 8 bytes and will be decrypted        with the already specified key. In PAD_NORMAL mode, if the        optional padding character is supplied, then the un-encrypted        data will have the padding characters removed from the end of        the bytes. This pad removal only occurs on the last 8 bytes of        the data (last data block). In PAD_PKCS5 mode, the special        padding end markers will be removed from the data after decrypting.        """        data = self._guardAgainstUnicode(data)        if pad is not None:            pad = self._guardAgainstUnicode(pad)        data = self.crypt(data, des.DECRYPT)        return self._unpadData(data, pad, padmode)##############################################################################                 Triple DES                    ##############################################################################class triple_des(_baseDes):    """Triple DES encryption/decrytpion class    This algorithm uses the DES-EDE3 (when a 24 byte key is supplied) or    the DES-EDE2 (when a 16 byte key is supplied) encryption methods.    Supports ECB (Electronic Code Book) and CBC (Cypher Block Chaining) modes.    pyDes.des(key, [mode], [IV])    key  -> Bytes containing the encryption key, must be either 16 orbytes long    mode -> Optional argument for encryption type, can be either pyDes.ECB        (Electronic Code Book), pyDes.CBC (Cypher Block Chaining)    IV   -> Optional Initial Value bytes, must be supplied if using CBC mode.        Must be 8 bytes in length.    pad  -> Optional argument, set the pad character (PAD_NORMAL) to use        during all encrypt/decrpt operations done with this instance.    padmode -> Optional argument, set the padding mode (PAD_NORMAL or        PAD_PKCS5) to use during all encrypt/decrpt operations done        with this instance.    """    def __init__(self, key, mode=ECB, IV=None, pad=None, padmode=PAD_NORMAL):        _baseDes.__init__(self, mode, IV, pad, padmode)        self.setKey(key)    def setKey(self, key):        """Will set the crypting key for this object. Either 16 or 24 bytes long."""        self.key_size = 24  # Use DES-EDE3 mode        if len(key) != self.key_size:            if len(key) == 16: # Use DES-EDE2 mode                self.key_size = 16            else:                raise ValueError("Invalid triple DES key size. Key must be either 16 or 24 bytes long")        if self.getMode() == CBC:            if not self.getIV():                # Use the first 8 bytes of the key                self._iv = key[:self.block_size]            if len(self.getIV()) != self.block_size:                raise ValueError("Invalid IV, must be 8 bytes in length")        self.__key1 = des(key[:8], self._mode, self._iv,                  self._padding, self._padmode)        self.__key2 = des(key[8:16], self._mode, self._iv,                  self._padding, self._padmode)        if self.key_size == 16:            self.__key3 = self.__key1        else:            self.__key3 = des(key[16:], self._mode, self._iv,                      self._padding, self._padmode)        _baseDes.setKey(self, key)    # Override setter methods to work on all 3 keys.    def setMode(self, mode):        """Sets the type of crypting mode, pyDes.ECB or pyDes.CBC"""        _baseDes.setMode(self, mode)        for key in (self.__key1, self.__key2, self.__key3):            key.setMode(mode)    def setPadding(self, pad):        """setPadding() -> bytes of length 1. Padding character."""        _baseDes.setPadding(self, pad)        for key in (self.__key1, self.__key2, self.__key3):            key.setPadding(pad)    def setPadMode(self, mode):        """Sets the type of padding mode, pyDes.PAD_NORMAL or pyDes.PAD_PKCS5"""        _baseDes.setPadMode(self, mode)        for key in (self.__key1, self.__key2, self.__key3):            key.setPadMode(mode)    def setIV(self, IV):        """Will set the Initial Value, used in conjunction with CBC mode"""        _baseDes.setIV(self, IV)        for key in (self.__key1, self.__key2, self.__key3):            key.setIV(IV)    def encrypt(self, data, pad=None, padmode=None):        """encrypt(data, [pad], [padmode]) -> bytes        data : bytes to be encrypted        pad  : Optional argument for encryption padding. Must only be one byte        padmode : Optional argument for overriding the padding mode.        The data must be a multiple of 8 bytes and will be encrypted        with the already specified key. Data does not have to be a        multiple of 8 bytes if the padding character is supplied, or        the padmode is set to PAD_PKCS5, as bytes will then added to        ensure the be padded data is a multiple of 8 bytes.        """        ENCRYPT = des.ENCRYPT        DECRYPT = des.DECRYPT        data = self._guardAgainstUnicode(data)        if pad is not None:            pad = self._guardAgainstUnicode(pad)        # Pad the data accordingly.        data = self._padData(data, pad, padmode)        if self.getMode() == CBC:            self.__key1.setIV(self.getIV())            self.__key2.setIV(self.getIV())            self.__key3.setIV(self.getIV())            i = 0            result = []            while i < len(data):                block = self.__key1.crypt(data[i:i+8], ENCRYPT)                block = self.__key2.crypt(block, DECRYPT)                block = self.__key3.crypt(block, ENCRYPT)                self.__key1.setIV(block)                self.__key2.setIV(block)                self.__key3.setIV(block)                result.append(block)                i += 8            if _pythonMajorVersion < 3:                return ''.join(result)            else:                return bytes.fromhex('').join(result)        else:            data = self.__key1.crypt(data, ENCRYPT)            data = self.__key2.crypt(data, DECRYPT)            return self.__key3.crypt(data, ENCRYPT)    def decrypt(self, data, pad=None, padmode=None):        """decrypt(data, [pad], [padmode]) -> bytes        data : bytes to be encrypted        pad  : Optional argument for decryption padding. Must only be one byte        padmode : Optional argument for overriding the padding mode.        The data must be a multiple of 8 bytes and will be decrypted        with the already specified key. In PAD_NORMAL mode, if the        optional padding character is supplied, then the un-encrypted        data will have the padding characters removed from the end of        the bytes. This pad removal only occurs on the last 8 bytes of        the data (last data block). In PAD_PKCS5 mode, the special        padding end markers will be removed from the data after        decrypting, no pad character is required for PAD_PKCS5.        """        ENCRYPT = des.ENCRYPT        DECRYPT = des.DECRYPT        data = self._guardAgainstUnicode(data)        if pad is not None:            pad = self._guardAgainstUnicode(pad)        if self.getMode() == CBC:            self.__key1.setIV(self.getIV())            self.__key2.setIV(self.getIV())            self.__key3.setIV(self.getIV())            i = 0            result = []            while i < len(data):                iv = data[i:i+8]                block = self.__key3.crypt(iv,    DECRYPT)                block = self.__key2.crypt(block, ENCRYPT)                block = self.__key1.crypt(block, DECRYPT)                self.__key1.setIV(iv)                self.__key2.setIV(iv)                self.__key3.setIV(iv)                result.append(block)                i += 8            if _pythonMajorVersion < 3:                data = ''.join(result)            else:                data = bytes.fromhex('').join(result)        else:            data = self.__key3.crypt(data, DECRYPT)            data = self.__key2.crypt(data, ENCRYPT)            data = self.__key1.crypt(data, DECRYPT)        return self._unpadData(data, pad, padmode)

test_pydes.py

from pyDes import *##############################################################################                 Examples                    ##############################################################################def _example_triple_des_():    from time import time    # Utility module    from binascii import unhexlify as unhex    # example shows triple-des encryption using the des class    print ("Example of triple DES encryption in default ECB mode (DES-EDE3)\n")    print ("Triple des using the des class (3 times)")    t = time()    k1 = des(unhex("133457799BBCDFF1"))    k2 = des(unhex("1122334455667788"))    k3 = des(unhex("77661100DD223311"))    d = "Triple DES test string, to be encrypted and decrypted..."    print ("Key1:      %r" % k1.getKey())    print ("Key2:      %r" % k2.getKey())    print ("Key3:      %r" % k3.getKey())    print ("Data:      %r" % d)    e1 = k1.encrypt(d)    e2 = k2.decrypt(e1)    e3 = k3.encrypt(e2)    print ("Encrypted: %r" % e3)    d3 = k3.decrypt(e3)    d2 = k2.encrypt(d3)    d1 = k1.decrypt(d2)    print ("Decrypted: %r" % d1)    print ("DES time taken: %f (%d crypt operations)" % (time() - t, 6 * (len(d) / 8)))    print ("")    # Example below uses the triple-des class to achieve the same as above    print ("Now using triple des class")    t = time()    t1 = triple_des(unhex("133457799BBCDFF1112233445566778877661100DD223311"))    print ("Key:       %r" % t1.getKey())    print ("Data:      %r" % d)    td1 = t1.encrypt(d)    print ("Encrypted: %r" % td1)    td2 = t1.decrypt(td1)    print ("Decrypted: %r" % td2)    print ("Triple DES time taken: %f (%d crypt operations)" % (time() - t, 6 * (len(d) / 8)))def _example_des_():    from time import time    # example of DES encrypting in CBC mode with the IV of "\0\0\0\0\0\0\0\0"    print ("Example of DES encryption using CBC mode\n")    t = time()    k = des("DESCRYPT", CBC, "\0\0\0\0\0\0\0\0")    data = "DES encryption algorithm"    print ("Key      : %r" % k.getKey())    print ("Data     : %r" % data)    d = k.encrypt(data)    print ("Encrypted: %r" % d)    d = k.decrypt(d)    print ("Decrypted: %r" % d)    print ("DES time taken: %f (6 crypt operations)" % (time() - t))    print ("")def _filetest_():    from time import time    f = open("pyDes.py", "rb+")    d = f.read()    f.close()    t = time()    k = des("MyDESKey")    d = k.encrypt(d, " ")    f = open("pyDes.py.enc", "wb+")    f.write(d)    f.close()        d = k.decrypt(d, " ")    f = open("pyDes.py.dec", "wb+")    f.write(d)    f.close()    print ("DES file test time: %f" % (time() - t))    def _profile_():    try:        import cProfile as profile    except:        import profile    profile.run('_fulltest_()')    #profile.run('_filetest_()')def _fulltest_():    # This should not produce any unexpected errors or exceptions    from time import time    from binascii import unhexlify as unhex    from binascii import hexlify as dohex    t = time()    data = "DES encryption algorithm".encode('ascii')    k = des("\0\0\0\0\0\0\0\0", CBC, "\0\0\0\0\0\0\0\0")    d = k.encrypt(data)    if k.decrypt(d) != data:        print ("Test 1:  Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 1:  Successful")    data = "Default string of text".encode('ascii')    k = des("\0\0\0\0\0\0\0\0", CBC, "\0\0\0\0\0\0\0\0")    d = k.encrypt(data, "*")    if k.decrypt(d, "*") != data:        print ("Test 2:  Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 2:  Successful")    data = "String to Pad".encode('ascii')    k = des("\r\n\tABC\r\n")    d = k.encrypt(data, "*")    if k.decrypt(d, "*") != data:        print ("Test 3:  Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 3:  Successful")    k = des("\r\n\tABC\r\n")    d = k.encrypt(unhex("000102030405060708FF8FDCB04080"), unhex("44"))    if k.decrypt(d, unhex("44")) != unhex("000102030405060708FF8FDCB04080"):        print ("Test 4a: Error: Unencypted data block does not match start data")    elif k.decrypt(d) != unhex("000102030405060708FF8FDCB0408044"):        print ("Test 4b: Error: Unencypted data block does not match start data")    else:        print ("Test 4:  Successful")    data = "String to Pad".encode('ascii')    k = des("\r\n\tkey\r\n")    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 5a: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    # Try same with padmode set on the class instance.    k = des("\r\n\tkey\r\n", padmode=PAD_PKCS5)    d = k.encrypt(data)    if k.decrypt(d) != data:        print ("Test 5b: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 5:  Successful")    k = triple_des("MyDesKey\r\n\tABC\r\n0987*543")    d = k.encrypt(unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"))    if k.decrypt(d) != unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"):        print ("Test 6:  Error: Unencypted data block does not match start data")    else:        print ("Test 6:  Successful")    k = triple_des("\r\n\tABC\r\n0987*543")    d = k.encrypt(unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"))    if k.decrypt(d) != unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"):        print ("Test 7:  Error: Unencypted data block does not match start data")    else:        print ("Test 7:  Successful")    k = triple_des("MyDesKey\r\n\tABC\r\n0987*54B", CBC, "12341234")    d = k.encrypt(unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"))    if k.decrypt(d) != unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"):        print ("Test 8:  Error: Triple DES CBC failed.")    else:        print ("Test 8:  Successful")    k = triple_des("MyDesKey\r\n\tABC\r\n0987*54B", CBC, "12341234")    d = k.encrypt(unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDC"), '.')    if k.decrypt(d, '.') != unhex("000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDC"):        print ("Test 9:  Error: Triple DES CBC with padding failed.")    else:        print ("Test 9:  Successful")    k = triple_des("\r\n\tkey\rIsGoodKey")    data = "String to Pad".encode('ascii')    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 10: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 10: Successful")    k = triple_des("\r\n\tkey\rIsGoodKey")    data = "String not need Padding.".encode('ascii')    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 11: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 11: Successful")    # Test PAD_PKCS5 with CBC encryption mode.    k = des("IGoodKey", mode=CBC, IV="\0\1\2\3\4\5\6\7")    data = "String to Pad".encode('ascii')    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 12: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 12: Successful")    k = des("IGoodKey", mode=CBC, IV="\0\1\2\3\4\5\6\7")    data = "String not need Padding.".encode('ascii')    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 13: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 13: Successful")    k = triple_des("\r\n\tkey\rIsGoodKey", mode=CBC, IV="\0\1\2\3\4\5\6\7")    data = "String to Pad".encode('ascii')    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 14: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 14: Successful")    k = triple_des("\r\n\tkey\rIsGoodKey", mode=CBC, IV="\0\1\2\3\4\5\6\7")    data = "String not need Padding.".encode('ascii')    d = k.encrypt(data, padmode=PAD_PKCS5)    if k.decrypt(d, padmode=PAD_PKCS5) != data:        print ("Test 15: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 15: Successful")    k = triple_des("\r\n\tkey\rIsGoodKey", mode=CBC, IV="\0\1\2\3\4\5\6\7", padmode=PAD_PKCS5)    data = "String to Pad".encode('ascii')    d = k.encrypt(data)    if k.decrypt(d) != data:        print ("Test 16: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 16: Successful")    # Ensure no error occurs when creating an instance with no IV yet set,    # test supplied by "Yoav Aner".    k = triple_des("\0" * 24, mode=CBC, pad=None, padmode=PAD_PKCS5)    data = "String to Pad".encode('ascii')    d = k.encrypt(data)    if k.decrypt(d) != data:        print ("Test 17: Error: decrypt does not match. %r != %r" % (data, k.decrypt(d)))    else:        print ("Test 17: Successful")    print ("")    print ("Total time taken: %f" % (time() - t))if __name__ == '__main__':    #_example_des_()    #_example_triple_des_()    _fulltest_()    #_profile_()

参考资料:http://www.cnblogs.com/txw1958/archive/2012/07/20/python-des-3des.html

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