本文实例讲述了python实现的DES加密算法和3DES加密算法。分享给大家供大家参考。具体实现方法如下:
#############################################################################
# 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 DES
mode -> 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 any
padding issues, as the padding can be removed unambiguously upon decrypting
data that was encrypted using PAD_PKCS5 padmode.
Common methods
--------------
encrypt(data, [pad], [padmode])
decrypt(data, [pad], [padmode])
data -> Bytes to be encrypted/decrypted
pad -> 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" % d
print "Decrypted: %r" % k.decrypt(d)
assert k.decrypt(d, padmode=PAD_PKCS5) == data
See 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 / cyphering
ECB = 0
CBC = 1
# Modes of padding
PAD_NORMAL = 1
PAD_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,
, 57, 49, 41, 33, 25, 17,
, 1, 58, 50, 42, 34, 26,
, 10, 2, 59, 51, 43, 35,
, 54, 46, 38, 30, 22, 14,
, 61, 53, 45, 37, 29, 21,
, 5, 60, 52, 44, 36, 28,
, 12, 4, 27, 19, 11, 3
]
# number left rotations of pc1
__left_rotations = [
, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
]
# permuted choice key (table 2)
__pc2 = [
, 16, 10, 23, 0, 4,
, 27, 14, 5, 20, 9,
, 18, 11, 3, 25, 7,
, 6, 26, 19, 12, 1,
, 51, 30, 36, 46, 54,
, 39, 50, 44, 32, 47,
, 48, 38, 55, 33, 52,
, 41, 49, 35, 28, 31
]
# initial permutation IP
__ip = [57, 49, 41, 33, 25, 17, 9, 1,
, 51, 43, 35, 27, 19, 11, 3,
, 53, 45, 37, 29, 21, 13, 5,
, 55, 47, 39, 31, 23, 15, 7,
, 48, 40, 32, 24, 16, 8, 0,
, 50, 42, 34, 26, 18, 10, 2,
, 52, 44, 36, 28, 20, 12, 4,
, 54, 46, 38, 30, 22, 14, 6
]
# Expansion table for turning 32 bit blocks into 48 bits
__expansion_table = [
, 0, 1, 2, 3, 4,
, 4, 5, 6, 7, 8,
, 8, 9, 10, 11, 12,
, 12, 13, 14, 15, 16,
, 16, 17, 18, 19, 20,
, 20, 21, 22, 23, 24,
, 24, 25, 26, 27, 28,
, 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,
, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
, 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,
, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
, 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,
, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
, 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,
, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
, 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,
, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
, 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,
, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
, 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,
, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
, 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,
, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
, 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 = [
, 6, 19, 20, 28, 11,
, 16, 0, 14, 22, 25,
, 17, 30, 9, 1, 7,
,13, 31, 26, 2, 8,
, 12, 29, 5, 21, 10,
, 24
]
# final permutation IP^-1
__fp = [
, 7, 47, 15, 55, 23, 63, 31,
, 6, 46, 14, 54, 22, 62, 30,
, 5, 45, 13, 53, 21, 61, 29,
, 4, 44, 12, 52, 20, 60, 28,
, 3, 43, 11, 51, 19, 59, 27,
, 2, 42, 10, 50, 18, 58, 26,
, 1, 41, 9, 49, 17, 57, 25,
, 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 or
bytes 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)
希望本文所述对大家的Python程序设计有所帮助。
京东创始人刘强东和其妻子章泽天最近成为了互联网舆论关注的焦点。有关他们“移民美国”和在美国购买豪宅的传言在互联网上广泛传播。然而,京东官方通过微博发言人发布的消息澄清了这些传言,称这些言论纯属虚假信息和蓄意捏造。
日前,据博主“@超能数码君老周”爆料,国内三大运营商中国移动、中国电信和中国联通预计将集体采购百万台规模的华为Mate60系列手机。
据报道,荷兰半导体设备公司ASML正看到美国对华遏制政策的负面影响。阿斯麦(ASML)CEO彼得·温宁克在一档电视节目中分享了他对中国大陆问题以及该公司面临的出口管制和保护主义的看法。彼得曾在多个场合表达了他对出口管制以及中荷经济关系的担忧。
今年早些时候,抖音悄然上线了一款名为“青桃”的 App,Slogan 为“看见你的热爱”,根据应用介绍可知,“青桃”是一个属于年轻人的兴趣知识视频平台,由抖音官方出品的中长视频关联版本,整体风格有些类似B站。
日前,威马汽车首席数据官梅松林转发了一份“世界各国地区拥车率排行榜”,同时,他发文表示:中国汽车普及率低于非洲国家尼日利亚,每百户家庭仅17户有车。意大利世界排名第一,每十户中九户有车。
近日,一项新的研究发现,维生素 C 和 E 等抗氧化剂会激活一种机制,刺激癌症肿瘤中新血管的生长,帮助它们生长和扩散。
据媒体援引消息人士报道,苹果公司正在测试使用3D打印技术来生产其智能手表的钢质底盘。消息传出后,3D系统一度大涨超10%,不过截至周三收盘,该股涨幅回落至2%以内。
9月2日,坐拥千万粉丝的网红主播“秀才”账号被封禁,在社交媒体平台上引发热议。平台相关负责人表示,“秀才”账号违反平台相关规定,已封禁。据知情人士透露,秀才近期被举报存在违法行为,这可能是他被封禁的部分原因。据悉,“秀才”年龄39岁,是安徽省亳州市蒙城县人,抖音网红,粉丝数量超1200万。他曾被称为“中老年...
9月3日消息,亚马逊的一些股东,包括持有该公司股票的一家养老基金,日前对亚马逊、其创始人贝索斯和其董事会提起诉讼,指控他们在为 Project Kuiper 卫星星座项目购买发射服务时“违反了信义义务”。
据消息,为推广自家应用,苹果现推出了一个名为“Apps by Apple”的网站,展示了苹果为旗下产品(如 iPhone、iPad、Apple Watch、Mac 和 Apple TV)开发的各种应用程序。
特斯拉本周在美国大幅下调Model S和X售价,引发了该公司一些最坚定支持者的不满。知名特斯拉多头、未来基金(Future Fund)管理合伙人加里·布莱克发帖称,降价是一种“短期麻醉剂”,会让潜在客户等待进一步降价。
据外媒9月2日报道,荷兰半导体设备制造商阿斯麦称,尽管荷兰政府颁布的半导体设备出口管制新规9月正式生效,但该公司已获得在2023年底以前向中国运送受限制芯片制造机器的许可。
近日,根据美国证券交易委员会的文件显示,苹果卫星服务提供商 Globalstar 近期向马斯克旗下的 SpaceX 支付 6400 万美元(约 4.65 亿元人民币)。用于在 2023-2025 年期间,发射卫星,进一步扩展苹果 iPhone 系列的 SOS 卫星服务。
据报道,马斯克旗下社交平台𝕏(推特)日前调整了隐私政策,允许 𝕏 使用用户发布的信息来训练其人工智能(AI)模型。新的隐私政策将于 9 月 29 日生效。新政策规定,𝕏可能会使用所收集到的平台信息和公开可用的信息,来帮助训练 𝕏 的机器学习或人工智能模型。
9月2日,荣耀CEO赵明在采访中谈及华为手机回归时表示,替老同事们高兴,觉得手机行业,由于华为的回归,让竞争充满了更多的可能性和更多的魅力,对行业来说也是件好事。
《自然》30日发表的一篇论文报道了一个名为Swift的人工智能(AI)系统,该系统驾驶无人机的能力可在真实世界中一对一冠军赛里战胜人类对手。
近日,非营利组织纽约真菌学会(NYMS)发出警告,表示亚马逊为代表的电商平台上,充斥着各种AI生成的蘑菇觅食科普书籍,其中存在诸多错误。
社交媒体平台𝕏(原推特)新隐私政策提到:“在您同意的情况下,我们可能出于安全、安保和身份识别目的收集和使用您的生物识别信息。”
2023年德国柏林消费电子展上,各大企业都带来了最新的理念和产品,而高端化、本土化的中国产品正在不断吸引欧洲等国际市场的目光。
罗永浩日前在直播中吐槽苹果即将推出的 iPhone 新品,具体内容为:“以我对我‘子公司’的了解,我认为 iPhone 15 跟 iPhone 14 不会有什么区别的,除了序(列)号变了,这个‘不要脸’的东西,这个‘臭厨子’。