This module provides access to a standardized implementation of SPICE (Stephen's Power-Inspired, Computerized Encryption).
This code has just been revised and rewritten. As such it may still contain bugs that were not found after testing the code.
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This module provides access to a standardized implementation
of SPICE (Stephen's Power-Inspired, Computerized Encryption).'''
################################################################################
__version__ = '$Revision: 0 $'
__date__ = 'April 19, 2008'
__author__ = 'Stephen "Zero" Chappell <my.bios@gmail.com>'
__credits__ = '''\
T. Parker, for testing code that led to this module.
A. Baddeley, for contributing to the random module.
R. Hettinger, for adding support for two core generators.'''
################################################################################
import random as _random
import sys as _sys
################################################################################
def crypt_major():
'Create a new Major Key.'
return ''.join(map(chr, _crypt.sample(xrange(256), 256)))
def crypt_minor():
'Create a new Minor Key.'
sample = _crypt.sample(range(4) * 64, 256)
array = []
for index in xrange(64):
bits_12 = sample[index * 4] << 6
bits_34 = sample[index * 4 + 1] << 4
bits_56 = sample[index * 4 + 2] << 2
bits_78 = sample[index * 4 + 3]
array.append(bits_12 + bits_34 + bits_56 + bits_78)
return ''.join(map(chr, array))
################################################################################
def named_major(name):
'Create a named Major Key.'
_namer.seed(name)
return ''.join(map(chr, _namer.sample(xrange(256), 256)))
def named_minor(name):
'Create a named Minor Key.'
_namer.seed(name)
sample = _namer.sample(range(4) * 64, 256)
array = []
for index in xrange(64):
bits_12 = sample[index * 4] << 6
bits_34 = sample[index * 4 + 1] << 4
bits_56 = sample[index * 4 + 2] << 2
bits_78 = sample[index * 4 + 3]
array.append(bits_12 + bits_34 + bits_56 + bits_78)
return ''.join(map(chr, array))
################################################################################
def encode_string(string, major, minor):
'Return an encrypted string.'
assert isinstance(string, str)
_check_major(major)
_check_minor(minor)
map_1 = _encode_map_1(major)
map_2 = _encode_map_2(minor)
return _encode(string, map_1, map_2)
def decode_string(string, major, minor):
'Return a decrypted string.'
assert isinstance(string, str) and len(string) % 4 == 0
_check_major(major)
_check_minor(minor)
map_1 = _decode_map_1(minor)
map_2 = _decode_map_2(major)
return _decode(string, map_1, map_2)
################################################################################
def encode_file(source, destination, major, minor):
'Encrypt a file from source to destination.'
_check_major(major)
_check_minor(minor)
map_1 = _encode_map_1(major)
map_2 = _encode_map_2(minor)
string = source.read(2 ** 20 / 5)
while string:
destination.write(_encode(string, map_1, map_2))
string = source.read(2 ** 20 / 5)
def decode_file(source, destination, major, minor):
'Decrypt a file from source to destination.'
_check_major(major)
_check_minor(minor)
map_1 = _decode_map_1(minor)
map_2 = _decode_map_2(major)
string = source.read(2 ** 20 / 5 * 4)
while string:
tail_len = len(string) % 4
if tail_len == 0:
destination.write(_decode(string, map_1, map_2))
string = source.read(2 ** 20 / 5 * 4)
else:
destination.write(_decode(string[:-tail_len], map_1, map_2))
return string[-tail_len:]
return ''
################################################################################
class File_Crypt:
'File_Crypt(major, minor, name, mode) -> File_Crypt'
def __init__(self, major, minor, name, mode):
'Initialize the File_Crypt object.'
_check_major(major)
_check_minor(minor)
self.__em1 = _encode_map_1(major)
self.__em2 = _encode_map_2(minor)
self.__dm1 = _decode_map_1(minor)
self.__dm2 = _decode_map_2(major)
assert len(mode) == 1 and mode in 'raw'
self.__file = open(name, mode + 'b', 0)
self.tail = ''
def read(self, size=-1):
'Read and decrypt from file.'
string = self.__file.read(size * 4)
tail_len = len(string) % 4
if tail_len:
self.tail = string[-tail_len:]
return _decode(string[:-tail_len], self.__dm1, self.__dm2)
else:
return _decode(string, self.__dm1, self.__dm2)
def write(self, string):
'Encrypt and write to file.'
self.__file.write(_encode(string, self.__em1, self.__em2))
def seek(self, offset, whence=0):
'Seek to virtual positon in file.'
self.__file.seek(offset * 4, whence)
offset = self.__file.tell() / 4
self.__file.seek(offset * 4)
def tell(self):
'Return the virtual position in file.'
return self.__file.tell() / 4
def close(self):
'Close the File_Crypt object.'
self.__file.close()
################################################################################
class Socket_Crypt:
'Socket_Crypt(major, minor, socket) -> Socket_Crypt'
def __init__(self, major, minor, socket):
'Initialize the Socket_Crypt object.'
_check_major(major)
_check_minor(minor)
self.__em1 = _encode_map_1(major)
self.__em2 = _encode_map_2(minor)
self.__dm1 = _decode_map_1(minor)
self.__dm2 = _decode_map_2(major)
self.__major = major
self.__minor = minor
self.__socket = socket
self.__tail = ''
self.__tails = {}
def accept(self):
'Return a new Socket_Crypt and address.'
conn, address = self.__socket.accept()
return Socket_Crypt(self.__major, self.__minor, conn), address
def recv(self, size, flags=0):
'Receive and decrypt off socket.'
string = self.__tail + self.__socket.recv(size * 4, flags)
tail_len = len(string) % 4
if tail_len:
self.__tail = string[-tail_len:]
return _decode(string[:-tail_len], self.__dm1, self.__dm2)
else:
self.__tail = ''
return _decode(string, self.__dm1, self.__dm2)
def recvfrom(self, size, flags=0):
'Receive datagram and decrypt off socket.'
string, address = self.__socket.recvfrom(size * 4, flags)
string = self.__tails.get(address, '') + string
tail_len = len(string) % 4
if tail_len:
self.__tails[address] = string[-tail_len:]
string = _decode(string[:-tail_len], self.__dm1, self.__dm2)
return string, address
else:
if address in self.__tails:
del self.__tails[address]
string = _decode(string, self.__dm1, self.__dm2)
return string, address
def send(self, string, flags=0):
'Encrypt and send on socket.'
string = _encode(string, self.__em1, self.__em2)
sent = self.__socket.send(string, flags)
offset = sent % 4
if offset:
string = string[sent:][:4-offset]
sent += len(string)
while string:
string = string[self.__socket.send(string, flags):]
return sent / 4
def sendall(self, string, flags=0):
'Encrypt and send all on socket.'
string = _encode(string, self.__em1, self.__em2)
return self.__socket.sendall(string, flags)
def sendto(self, string, address, flags=0):
'Encrypt and send datagram on socket.'
string = _encode(string, self.__em1, self.__em2)
sent = self.__socket.sendto(string, flags, address)
offset = sent % 4
if offset:
string = string[sent:][:4-offset]
sent += len(string)
while string:
string = string[self.socket.sentto(string, flags, address):]
return sent / 4
def makefile(self, mode='r', bufsize=-1):
'Return a file-like object.'
return self
def read(self, size=-1):
'Read and decrypt from socket.'
if size < 0:
cache = ''
while True:
temp = self.recv(2 ** 10)
if temp:
cache += temp
else:
return cache
else:
return self.recv(size)
def readline(self, size=-1):
'Dummy attribute for cPickle.'
raise NotImplementedError
def write(self, string):
'Encrypt and write to socket.'
self.sendall(string)
################################################################################
class String_Crypt:
'String_Crypt(major, minor) -> String_Crypt'
def __init__(self, major, minor):
'Initialize the String_Crypt object.'
_check_major(major)
_check_minor(minor)
self.__em1 = _encode_map_1(major)
self.__em2 = _encode_map_2(minor)
self.__dm1 = _decode_map_1(minor)
self.__dm2 = _decode_map_2(major)
def encode(self, string):
'Return an encrypted string.'
assert isinstance(string, str)
return _encode(string, self.__em1, self.__em2)
def decode(self, string):
'Return a decrypted string.'
assert isinstance(string, str) and len(string) % 4 == 0
return _decode(string, self.__dm1, self.__dm2)
################################################################################
_crypt = _random.SystemRandom()
_namer = _random.Random()
################################################################################
def _check_major(key):
'Private module function.'
assert isinstance(key, str) and len(key) == 256
for character in map(chr, xrange(256)):
assert character in key
def _check_minor(key):
'Private module function.'
assert isinstance(key, str) and len(key) == 64
indexs = []
for byte in map(ord, key):
for shift in xrange(6, -2, -2):
indexs.append((byte >> shift) & 3)
for index in xrange(4):
assert indexs.count(index) == 64
def _encode_map_1(major):
'Private module function.'
return map(ord, major)
def _encode_map_2(minor):
'Private module function.'
map_2 = [[], [], [], []]
array = []
for byte in map(ord, minor):
for shift in xrange(6, -2, -2):
array.append((byte >> shift) & 3)
for byte, index in enumerate(array):
map_2[index].append(chr(byte))
return map_2
def _decode_map_1(minor):
'Private module function.'
map_1 = []
for byte in map(ord, minor):
for shift in xrange(6, -2, -2):
map_1.append((byte >> shift) & 3)
return map_1
def _decode_map_2(major):
'Private module function.'
map_2 = [None] * 256
for byte, index in enumerate(map(ord, major)):
map_2[index] = chr(byte)
return map_2
def _encode(string, map_1, map_2):
'Private module function.'
cache = ''
for character in string:
byte = map_1[ord(character)]
for shift in xrange(6, -2, -2):
cache += map_2[(byte >> shift) & 3][_crypt.randrange(64)]
return cache
def _decode(string, map_1, map_2):
'Private module function.'
cache = ''
iterator = iter(string)
for byte in iterator:
bits_12 = map_1[ord(byte)] << 6
bits_34 = map_1[ord(iterator.next())] << 4
bits_56 = map_1[ord(iterator.next())] << 2
bits_78 = map_1[ord(iterator.next())]
cache += map_2[bits_12 + bits_34 + bits_56 + bits_78]
return cache
################################################################################
if __name__ == '__main__':
_sys.stdout.write('Content-Type: text/plain\n\n')
_sys.stdout.write(file(_sys.argv[0]).read())
|
Tags: algorithms
