Permalink
Cannot retrieve contributors at this time
810 lines (666 sloc)
28.4 KB
| # ############################################################################ | |
| # Documentation # | |
| ############################################################################# | |
| # Author: Todd Whiteman | |
| # Date: 7th May, 2003 | |
| # Verion: 1.1 | |
| # Homepage: http://home.pacific.net.au/~twhitema/des.html | |
| # | |
| # 10/13/2020 - Updates by luke@socially-inept.net made to make module | |
| # compatible with Python3, corrected a few very minor | |
| # PIP things. | |
| # | |
| # Modifications to 3des CBC code by Matt Johnston 2004 <matt at ucc asn au> | |
| # | |
| # This algorithm is a pure python implementation of the DES algorithm. | |
| # It is in 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. | |
| """A pure python implementation of the DES and TRIPLE DES encryption algorithms | |
| pyDes.des(key, [mode], [IV]) | |
| pyDes.triple_des(key, [mode], [IV]) | |
| key -> String 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 argument, must be supplied if using CBC mode. Must be 8 bytes | |
| Example: | |
| from pyDes import * | |
| data = "Please encrypt my string" | |
| k = des("DESCRYPT", " ", CBC, "\0\0\0\0\0\0\0\0") | |
| d = k.encrypt(data) | |
| print("Encypted string: " + d) | |
| print("Decypted string: " + k.decrypt(d)) | |
| See the module source (pyDes.py) for more examples of use. | |
| You can slo 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. | |
| """ | |
| # Modes of crypting / cyphering | |
| ECB = 0 | |
| CBC = 1 | |
| ############################################################################# | |
| # DES # | |
| ############################################################################# | |
| class DES(object): | |
| """DES encryption/decrytpion class | |
| Supports ECB (Electronic Code Book) and CBC (Cypher Block Chaining) modes. | |
| pyDes.des(key,[mode], [IV]) | |
| key -> The encryption key string, 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 string argument, must be supplied if using CBC mode. | |
| Must be 8 bytes in length. | |
| """ | |
| # 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): | |
| if len(key) != 8: | |
| raise ValueError("Invalid DES key size. Key must be exactly 8 bytes long.") | |
| self.block_size = 8 | |
| self.key_size = 8 | |
| self.__padding = '' | |
| # Set the passed in variables | |
| self.setMode(mode) | |
| if IV: | |
| self.setIV(IV) | |
| self.L = [] | |
| self.R = [] | |
| self.Kn = [[0] * 48] * 16 # 16 48-bit keys (K1 - K16) | |
| self.final = [] | |
| self.setKey(key) | |
| def getKey(self): | |
| """getKey() -> string""" | |
| return self.__key | |
| def setKey(self, key): | |
| """Will set the crypting key for this object. Must be 8 bytes.""" | |
| self.__key = key | |
| self.__create_sub_keys() | |
| 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 getIV(self): | |
| """getIV() -> string""" | |
| 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") | |
| self.__iv = IV | |
| def getPadding(self): | |
| """getPadding() -> string of length 1. Padding character.""" | |
| return self.__padding | |
| def __String_to_BitList(self, data): | |
| """Turn the string data, into a list of bits (1, 0)'s""" | |
| l = len(data) * 8 | |
| result = [0] * l | |
| pos = 0 | |
| for c in data: | |
| i = 7 | |
| ch = ord(c) | |
| 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 += chr(c) | |
| c = 0 | |
| pos += 1 | |
| return result | |
| def __permutate(self, table, block): | |
| """Permutate this block with the specified table""" | |
| return 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 = 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 = 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 = 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 = 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)) | |
| # Remove the padding from the last block | |
| if crypt_type == DES.DECRYPT and self.getPadding(): | |
| # print("Removing decrypt pad") | |
| s = result[-1] | |
| while s[-1] == self.getPadding(): | |
| s = s[:-1] | |
| result[-1] = s | |
| # Return the full crypted string | |
| return ''.join(result) | |
| def encrypt(self, data, pad=''): | |
| """ | |
| encrypt(data, [pad]) -> string | |
| data : String to be encrypted | |
| pad : Optional argument for encryption padding. Must only be one byte | |
| 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, the | |
| data will then be padded to a multiple of 8 bytes with this | |
| pad character. | |
| """ | |
| self.__padding = pad | |
| return self.crypt(data, DES.ENCRYPT) | |
| def decrypt(self, data, pad=''): | |
| """ | |
| decrypt(data, [pad]) -> string | |
| data : String to be encrypted | |
| pad : Optional argument for decryption padding. Must only be one byte | |
| The data must be a multiple of 8 bytes and will be decrypted | |
| with the already specified key. If the optional padding character | |
| is supplied, then the un-encypted data will have the padding characters | |
| removed from the end of the string. This pad removal only occurs on the | |
| last 8 bytes of the data (last data block). | |
| """ | |
| self.__padding = pad | |
| return self.crypt(data, DES.DECRYPT) | |
| ############################################################################# | |
| # Triple DES # | |
| ############################################################################# | |
| class TripleDES(object): | |
| """ | |
| 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 -> The encryption key string, must be either 16 or 24 bytes long | |
| mode -> Optional argument for encryption type, can be either pyDes.ECB | |
| (Electronic Code Book), pyDes.CBC (Cypher Block Chaining) | |
| IV -> Optional string argument, must be supplied if using CBC mode. | |
| Must be 8 bytes in length. | |
| """ | |
| def __init__(self, key, mode=ECB, IV=None): | |
| self.block_size = 8 | |
| self.setMode(mode) | |
| self.__padding = '' | |
| self.__iv = IV | |
| self.setKey(key) | |
| def getKey(self): | |
| """getKey() -> string""" | |
| return self.__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 and (not self.getIV() or len(self.getIV()) != self.block_size): | |
| raise ValueError("Invalid IV, must be 8 bytes in length") ## TODO: Check this | |
| # modes get handled later, since CBC goes on top of the triple-des | |
| self.__key1 = DES(key[:8]) | |
| self.__key2 = DES(key[8:16]) | |
| if self.key_size == 16: | |
| self.__key3 = self.__key1 | |
| else: | |
| self.__key3 = DES(key[16:]) | |
| 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 getIV(self): | |
| """getIV() -> string""" | |
| return self.__iv | |
| def setIV(self, IV): | |
| """Will set the Initial Value, used in conjunction with CBC mode""" | |
| self.__iv = IV | |
| def xorstr(self, x, y): | |
| """Returns the bitwise xor of the bytes in two strings""" | |
| if len(x) != len(y): | |
| raise Exception("string lengths differ %d %d" % (len(x), len(y))) | |
| ret = '' | |
| for i in range(len(x)): | |
| ret += chr(ord(x[i]) ^ ord(y[i])) | |
| return ret | |
| def encrypt(self, data, pad=''): | |
| """ | |
| encrypt(data, [pad]) -> string | |
| data : String to be encrypted | |
| pad : Optional argument for encryption padding. Must only be one byte | |
| 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, the | |
| data will then be padded to a multiple of 8 bytes with this | |
| pad character. | |
| """ | |
| if self.getMode() == ECB: | |
| # simple | |
| data = self.__key1.encrypt(data, pad) | |
| data = self.__key2.decrypt(data) | |
| return self.__key3.encrypt(data) | |
| if self.getMode() == CBC: | |
| raise Exception("This code hasn't been tested yet") | |
| if len(data) % self.block_size != 0: | |
| raise Exception("CBC mode needs datalen to be a multiple of blocksize (ignoring padding for now)") | |
| # simple | |
| lastblock = self.getIV() | |
| retdata = '' | |
| for i in range(0, len(data), self.block_size): | |
| thisblock = data[i:i + self.block_size] | |
| # the XOR for CBC | |
| thisblock = self._xorstr(lastblock, thisblock) | |
| thisblock = self.__key1.encrypt(thisblock) | |
| thisblock = self.__key2.decrypt(thisblock) | |
| lastblock = self.__key3.encrypt(thisblock) | |
| retdata += lastblock | |
| return retdata | |
| raise Exception("Not reached") | |
| def decrypt(self, data, pad=''): | |
| """ | |
| decrypt(data, [pad]) -> string | |
| data : String to be encrypted | |
| pad : Optional argument for decryption padding. Must only be one byte | |
| The data must be a multiple of 8 bytes and will be decrypted | |
| with the already specified key. If the optional padding character | |
| is supplied, then the un-encypted data will have the padding characters | |
| removed from the end of the string. This pad removal only occurs on the | |
| last 8 bytes of the data (last data block). | |
| """ | |
| if self.getMode() == ECB: | |
| # simple | |
| data = self.__key3.decrypt(data) | |
| data = self.__key2.encrypt(data) | |
| return self.__key1.decrypt(data, pad) | |
| if self.getMode() == CBC: | |
| if len(data) % self.block_size != 0: | |
| raise Exception("Can only decrypt multiples of blocksize") | |
| lastblock = self.getIV() | |
| retdata = '' | |
| for i in range(0, len(data), self.block_size): | |
| # can I arrange this better? probably... | |
| cipherchunk = data[i:i + self.block_size] | |
| thisblock = self.__key3.decrypt(cipherchunk) | |
| thisblock = self.__key2.encrypt(thisblock) | |
| thisblock = self.__key1.decrypt(thisblock) | |
| retdata += self.xorstr(lastblock, thisblock) | |
| lastblock = cipherchunk | |
| return retdata | |
| raise Exception("Not reached") | |
| ############################################################################# | |
| # 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: %s" % k1.getKey()) | |
| # print("Key2: %s" % k2.getKey()) | |
| # print("Key3: %s" % k3.getKey()) | |
| # print("Data: %s" % d) | |
| e1 = k1.encrypt(d) | |
| e2 = k2.decrypt(e1) | |
| e3 = k3.encrypt(e2) | |
| # print("Encrypted: " + e3) | |
| d3 = k3.decrypt(e3) | |
| d2 = k2.encrypt(d3) | |
| d1 = k1.decrypt(d2) | |
| # print("Decrypted: " + 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 = TripleDES(unhex("133457799BBCDFF1112233445566778877661100DD223311")) | |
| # print("Key: %s" % t1.getKey()) | |
| # print("Data: %s" % d) | |
| td1 = t1.encrypt(d) | |
| # print("Encrypted: " + td1) | |
| td2 = t1.decrypt(td1) | |
| # print("Decrypted: " + 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 : " + k.getKey()) | |
| # print("Data : " + data) | |
| d = k.encrypt(data) | |
| # print("Encrypted: " + d) | |
| d = k.decrypt(d) | |
| # print("Decrypted: " + d) | |
| # print("DES time taken: %f (6 crypt operations)" % (time() - t)) | |
| # print("") | |
| def __test__(): | |
| example_des() | |
| example_triple_des() | |
| def __fulltest__(): | |
| # This should not produce any unexpected errors or exceptions | |
| from binascii import unhexlify as unhex | |
| from binascii import hexlify as dohex | |
| __test__() | |
| # print("") | |
| k = DES("\0\0\0\0\0\0\0\0", CBC, "\0\0\0\0\0\0\0\0") | |
| d = k.encrypt("DES encryption algorithm") | |
| if k.decrypt(d) != "DES encryption algorithm": | |
| print("Test 1 Error: Unencypted data block does not match start data") | |
| k = DES("\0\0\0\0\0\0\0\0", CBC, "\0\0\0\0\0\0\0\0") | |
| d = k.encrypt("Default string of text", '*') | |
| if k.decrypt(d, "*") != "Default string of text": | |
| print("Test 2 Error: Unencypted data block does not match start data") | |
| k = DES("\r\n\tABC\r\n") | |
| d = k.encrypt("String to Pad", '*') | |
| if k.decrypt(d) != "String to Pad***": | |
| print("'%s'" % k.decrypt(d)) | |
| print("Test 3 Error: Unencypted data block does not match start data") | |
| 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") | |
| if k.decrypt(d) != unhex("000102030405060708FF8FDCB0408044"): | |
| print("Test 4b Error: Unencypted data block does not match start data") | |
| k = TripleDES("MyDesKey\r\n\tABC\r\n0987*543") | |
| d = k.encrypt(unhex( | |
| "000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080")) | |
| if k.decrypt(d) != unhex( | |
| "000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080000102030405060708FF8FDCB04080"): | |
| print("Test 5 Error: Unencypted data block does not match start data") | |
| k = TripleDES("\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") | |
| 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__(): | |
| import profile | |
| profile.run('__fulltest__()') | |
| # profile.run('__filetest__()') | |
| if __name__ == '__main__': | |
| __test__() | |
| # __fulltest__() | |
| # __filetest__() | |
| # __profile__() |