624 lines
14 KiB
C
624 lines
14 KiB
C
/***********************************************************
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Copyright 1994 by Lance Ellinghouse,
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Cathedral City, California Republic, United States of America.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
|
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the name of Lance Ellinghouse
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not be used in advertising or publicity pertaining to distribution
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of the software without specific, written prior permission.
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LANCE ELLINGHOUSE DISCLAIMS ALL WARRANTIES WITH REGARD TO
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THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS, IN NO EVENT SHALL LANCE ELLINGHOUSE BE LIABLE FOR ANY SPECIAL,
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INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
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FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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******************************************************************/
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/* This creates an encryption and decryption engine I am calling
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a rotor due to the original design was a hardware rotor with
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contacts used in Germany during WWII.
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Rotor Module:
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- rotor.newrotor('key') -> rotorobject (default of 6 rotors)
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- rotor.newrotor('key', num_rotors) -> rotorobject
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Rotor Objects:
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- ro.setkey('string') -> None (resets the key as defined in newrotor().
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- ro.encrypt('string') -> encrypted string
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- ro.decrypt('encrypted string') -> unencrypted string
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- ro.encryptmore('string') -> encrypted string
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- ro.decryptmore('encrypted string') -> unencrypted string
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NOTE: the {en,de}cryptmore() methods use the setup that was
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established via the {en,de}crypt calls. They will NOT
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re-initalize the rotors unless: 1) They have not been
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initialized with {en,de}crypt since the last setkey() call;
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2) {en,de}crypt has not been called for this rotor yet.
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NOTE: you MUST use the SAME key in rotor.newrotor()
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if you wish to decrypt an encrypted string.
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Also, the encrypted string is NOT 0-127 ASCII.
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It is considered BINARY data.
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*/
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/* Rotor objects */
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#include "Python.h"
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#ifndef TRUE
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#define TRUE 1
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#endif
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#ifndef FALSE
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#define FALSE 0
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#endif
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typedef struct {
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PyObject_HEAD
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int seed[3];
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short key[5];
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int isinited;
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int size;
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int size_mask;
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int rotors;
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unsigned char *e_rotor; /* [num_rotors][size] */
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unsigned char *d_rotor; /* [num_rotors][size] */
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unsigned char *positions; /* [num_rotors] */
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unsigned char *advances; /* [num_rotors] */
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} Rotorobj;
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static PyTypeObject Rotor_Type;
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#define is_rotor(v) ((v)->ob_type == &Rotor_Type)
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/* This defines the necessary routines to manage rotor objects */
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static void
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set_seed(Rotorobj *r)
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{
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r->seed[0] = r->key[0];
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r->seed[1] = r->key[1];
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r->seed[2] = r->key[2];
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r->isinited = FALSE;
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}
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/* Return the next random number in the range [0.0 .. 1.0) */
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static double
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r_random(Rotorobj *r)
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{
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int x, y, z;
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double val, term;
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x = r->seed[0];
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y = r->seed[1];
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z = r->seed[2];
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x = 171 * (x % 177) - 2 * (x/177);
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y = 172 * (y % 176) - 35 * (y/176);
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z = 170 * (z % 178) - 63 * (z/178);
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if (x < 0) x = x + 30269;
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if (y < 0) y = y + 30307;
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if (z < 0) z = z + 30323;
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r->seed[0] = x;
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r->seed[1] = y;
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r->seed[2] = z;
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term = (double)(
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(((double)x)/(double)30269.0) +
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(((double)y)/(double)30307.0) +
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(((double)z)/(double)30323.0)
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);
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val = term - (double)floor((double)term);
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if (val >= 1.0)
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val = 0.0;
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return val;
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}
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static short
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r_rand(Rotorobj *r, short s)
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{
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return (short)((short)(r_random(r) * (double)s) % s);
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}
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static void
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set_key(Rotorobj *r, char *key)
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{
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unsigned long k1=995, k2=576, k3=767, k4=671, k5=463;
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size_t i;
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size_t len = strlen(key);
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for (i = 0; i < len; i++) {
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unsigned short ki = Py_CHARMASK(key[i]);
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k1 = (((k1<<3 | k1>>13) + ki) & 65535);
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k2 = (((k2<<3 | k2>>13) ^ ki) & 65535);
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k3 = (((k3<<3 | k3>>13) - ki) & 65535);
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k4 = ((ki - (k4<<3 | k4>>13)) & 65535);
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k5 = (((k5<<3 | k5>>13) ^ ~ki) & 65535);
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}
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r->key[0] = (short)k1;
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r->key[1] = (short)(k2|1);
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r->key[2] = (short)k3;
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r->key[3] = (short)k4;
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r->key[4] = (short)k5;
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set_seed(r);
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}
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/* These define the interface to a rotor object */
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static Rotorobj *
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rotorobj_new(int num_rotors, char *key)
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{
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Rotorobj *xp;
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xp = PyObject_New(Rotorobj, &Rotor_Type);
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if (xp == NULL)
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return NULL;
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set_key(xp, key);
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xp->size = 256;
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xp->size_mask = xp->size - 1;
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xp->size_mask = 0;
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xp->rotors = num_rotors;
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xp->e_rotor = NULL;
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xp->d_rotor = NULL;
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xp->positions = NULL;
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xp->advances = NULL;
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if (!(xp->e_rotor = PyMem_NEW(unsigned char, num_rotors * xp->size)))
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goto finally;
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if (!(xp->d_rotor = PyMem_NEW(unsigned char, num_rotors * xp->size)))
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goto finally;
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if (!(xp->positions = PyMem_NEW(unsigned char, num_rotors)))
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goto finally;
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if (!(xp->advances = PyMem_NEW(unsigned char, num_rotors)))
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goto finally;
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return xp;
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finally:
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if (xp->e_rotor)
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PyMem_DEL(xp->e_rotor);
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if (xp->d_rotor)
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PyMem_DEL(xp->d_rotor);
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if (xp->positions)
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PyMem_DEL(xp->positions);
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if (xp->advances)
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PyMem_DEL(xp->advances);
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Py_DECREF(xp);
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return (Rotorobj*)PyErr_NoMemory();
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}
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/* These routines implement the rotor itself */
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/* Here is a fairly sophisticated {en,de}cryption system. It is based on
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the idea of a "rotor" machine. A bunch of rotors, each with a
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different permutation of the alphabet, rotate around a different amount
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after encrypting one character. The current state of the rotors is
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used to encrypt one character.
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The code is smart enough to tell if your alphabet has a number of
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characters equal to a power of two. If it does, it uses logical
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operations, if not it uses div and mod (both require a division).
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You will need to make two changes to the code 1) convert to c, and
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customize for an alphabet of 255 chars 2) add a filter at the begining,
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and end, which subtracts one on the way in, and adds one on the way
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out.
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You might wish to do some timing studies. Another viable alternative
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is to "byte stuff" the encrypted data of a normal (perhaps this one)
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encryption routine.
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j'
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*/
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/* Note: the C code here is a fairly straightforward transliteration of a
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* rotor implemented in lisp. The original lisp code has been removed from
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* this file to for simplification, but I've kept the docstrings as
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* comments in front of the functions.
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*/
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/* Set ROTOR to the identity permutation */
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static void
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RTR_make_id_rotor(Rotorobj *r, unsigned char *rtr)
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{
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register int j;
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register int size = r->size;
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for (j = 0; j < size; j++) {
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rtr[j] = (unsigned char)j;
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}
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}
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/* The current set of encryption rotors */
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static void
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RTR_e_rotors(Rotorobj *r)
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{
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int i;
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for (i = 0; i < r->rotors; i++) {
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RTR_make_id_rotor(r, &(r->e_rotor[(i*r->size)]));
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}
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}
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/* The current set of decryption rotors */
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static void
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RTR_d_rotors(Rotorobj *r)
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{
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register int i, j;
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for (i = 0; i < r->rotors; i++) {
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for (j = 0; j < r->size; j++) {
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r->d_rotor[((i*r->size)+j)] = (unsigned char)j;
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}
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}
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}
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/* The positions of the rotors at this time */
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static void
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RTR_positions(Rotorobj *r)
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{
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int i;
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for (i = 0; i < r->rotors; i++) {
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r->positions[i] = 1;
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}
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}
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/* The number of positions to advance the rotors at a time */
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static void
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RTR_advances(Rotorobj *r)
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{
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int i;
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for (i = 0; i < r->rotors; i++) {
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r->advances[i] = 1;
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}
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}
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/* Permute the E rotor, and make the D rotor its inverse
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* see Knuth for explanation of algorithm.
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*/
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static void
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RTR_permute_rotor(Rotorobj *r, unsigned char *e, unsigned char *d)
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{
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short i = r->size;
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short q;
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unsigned char j;
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RTR_make_id_rotor(r,e);
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while (2 <= i) {
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q = r_rand(r,i);
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i--;
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j = e[q];
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e[q] = (unsigned char)e[i];
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e[i] = (unsigned char)j;
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d[j] = (unsigned char)i;
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}
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e[0] = (unsigned char)e[0];
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d[(e[0])] = (unsigned char)0;
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}
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/* Given KEY (a list of 5 16 bit numbers), initialize the rotor machine.
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* Set the advancement, position, and permutation of the rotors
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*/
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static void
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RTR_init(Rotorobj *r)
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{
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int i;
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set_seed(r);
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RTR_positions(r);
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RTR_advances(r);
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RTR_e_rotors(r);
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RTR_d_rotors(r);
|
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for (i = 0; i < r->rotors; i++) {
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r->positions[i] = (unsigned char) r_rand(r, (short)r->size);
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r->advances[i] = (1+(2*(r_rand(r, (short)(r->size/2)))));
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RTR_permute_rotor(r,
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&(r->e_rotor[(i*r->size)]),
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&(r->d_rotor[(i*r->size)]));
|
||
}
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r->isinited = TRUE;
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}
|
||
|
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/* Change the RTR-positions vector, using the RTR-advances vector */
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static void
|
||
RTR_advance(Rotorobj *r)
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{
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register int i=0, temp=0;
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if (r->size_mask) {
|
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while (i < r->rotors) {
|
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temp = r->positions[i] + r->advances[i];
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||
r->positions[i] = temp & r->size_mask;
|
||
if ((temp >= r->size) && (i < (r->rotors - 1))) {
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r->positions[(i+1)] = 1 + r->positions[(i+1)];
|
||
}
|
||
i++;
|
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}
|
||
} else {
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while (i < r->rotors) {
|
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temp = r->positions[i] + r->advances[i];
|
||
r->positions[i] = temp%r->size;
|
||
if ((temp >= r->size) && (i < (r->rotors - 1))) {
|
||
r->positions[(i+1)] = 1 + r->positions[(i+1)];
|
||
}
|
||
i++;
|
||
}
|
||
}
|
||
}
|
||
|
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/* Encrypt the character P with the current rotor machine */
|
||
static unsigned char
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||
RTR_e_char(Rotorobj *r, unsigned char p)
|
||
{
|
||
register int i=0;
|
||
register unsigned char tp=p;
|
||
if (r->size_mask) {
|
||
while (i < r->rotors) {
|
||
tp = r->e_rotor[(i*r->size) +
|
||
(((r->positions[i] ^ tp) &
|
||
r->size_mask))];
|
||
i++;
|
||
}
|
||
} else {
|
||
while (i < r->rotors) {
|
||
tp = r->e_rotor[(i*r->size) +
|
||
(((r->positions[i] ^ tp) %
|
||
(unsigned int) r->size))];
|
||
i++;
|
||
}
|
||
}
|
||
RTR_advance(r);
|
||
return ((unsigned char)tp);
|
||
}
|
||
|
||
/* Decrypt the character C with the current rotor machine */
|
||
static unsigned char
|
||
RTR_d_char(Rotorobj *r, unsigned char c)
|
||
{
|
||
register int i = r->rotors - 1;
|
||
register unsigned char tc = c;
|
||
|
||
if (r->size_mask) {
|
||
while (0 <= i) {
|
||
tc = (r->positions[i] ^
|
||
r->d_rotor[(i*r->size)+tc]) & r->size_mask;
|
||
i--;
|
||
}
|
||
} else {
|
||
while (0 <= i) {
|
||
tc = (r->positions[i] ^
|
||
r->d_rotor[(i*r->size)+tc]) %
|
||
(unsigned int) r->size;
|
||
i--;
|
||
}
|
||
}
|
||
RTR_advance(r);
|
||
return(tc);
|
||
}
|
||
|
||
/* Perform a rotor encryption of the region from BEG to END by KEY */
|
||
static void
|
||
RTR_e_region(Rotorobj *r, unsigned char *beg, int len, int doinit)
|
||
{
|
||
register int i;
|
||
if (doinit || r->isinited == FALSE)
|
||
RTR_init(r);
|
||
for (i = 0; i < len; i++) {
|
||
beg[i] = RTR_e_char(r, beg[i]);
|
||
}
|
||
}
|
||
|
||
/* Perform a rotor decryption of the region from BEG to END by KEY */
|
||
static void
|
||
RTR_d_region(Rotorobj *r, unsigned char *beg, int len, int doinit)
|
||
{
|
||
register int i;
|
||
if (doinit || r->isinited == FALSE)
|
||
RTR_init(r);
|
||
for (i = 0; i < len; i++) {
|
||
beg[i] = RTR_d_char(r, beg[i]);
|
||
}
|
||
}
|
||
|
||
|
||
|
||
/* Rotor methods */
|
||
static void
|
||
rotor_dealloc(Rotorobj *xp)
|
||
{
|
||
if (xp->e_rotor)
|
||
PyMem_DEL(xp->e_rotor);
|
||
if (xp->d_rotor)
|
||
PyMem_DEL(xp->d_rotor);
|
||
if (xp->positions)
|
||
PyMem_DEL(xp->positions);
|
||
if (xp->advances)
|
||
PyMem_DEL(xp->advances);
|
||
PyObject_Del(xp);
|
||
}
|
||
|
||
static PyObject *
|
||
rotorobj_encrypt(Rotorobj *self, PyObject *args)
|
||
{
|
||
char *string = NULL;
|
||
int len = 0;
|
||
PyObject *rtn = NULL;
|
||
char *tmp;
|
||
|
||
if (!PyArg_ParseTuple(args, "s#:encrypt", &string, &len))
|
||
return NULL;
|
||
if (!(tmp = PyMem_NEW(char, len+5))) {
|
||
PyErr_NoMemory();
|
||
return NULL;
|
||
}
|
||
memset(tmp, '\0', len+1);
|
||
memcpy(tmp, string, len);
|
||
RTR_e_region(self, (unsigned char *)tmp, len, TRUE);
|
||
rtn = PyString_FromStringAndSize(tmp, len);
|
||
PyMem_DEL(tmp);
|
||
return(rtn);
|
||
}
|
||
|
||
static PyObject *
|
||
rotorobj_encrypt_more(Rotorobj *self, PyObject *args)
|
||
{
|
||
char *string = NULL;
|
||
int len = 0;
|
||
PyObject *rtn = NULL;
|
||
char *tmp;
|
||
|
||
if (!PyArg_ParseTuple(args, "s#:encrypt_more", &string, &len))
|
||
return NULL;
|
||
if (!(tmp = PyMem_NEW(char, len+5))) {
|
||
PyErr_NoMemory();
|
||
return NULL;
|
||
}
|
||
memset(tmp, '\0', len+1);
|
||
memcpy(tmp, string, len);
|
||
RTR_e_region(self, (unsigned char *)tmp, len, FALSE);
|
||
rtn = PyString_FromStringAndSize(tmp, len);
|
||
PyMem_DEL(tmp);
|
||
return(rtn);
|
||
}
|
||
|
||
static PyObject *
|
||
rotorobj_decrypt(Rotorobj *self, PyObject *args)
|
||
{
|
||
char *string = NULL;
|
||
int len = 0;
|
||
PyObject *rtn = NULL;
|
||
char *tmp;
|
||
|
||
if (!PyArg_ParseTuple(args, "s#:decrypt", &string, &len))
|
||
return NULL;
|
||
if (!(tmp = PyMem_NEW(char, len+5))) {
|
||
PyErr_NoMemory();
|
||
return NULL;
|
||
}
|
||
memset(tmp, '\0', len+1);
|
||
memcpy(tmp, string, len);
|
||
RTR_d_region(self, (unsigned char *)tmp, len, TRUE);
|
||
rtn = PyString_FromStringAndSize(tmp, len);
|
||
PyMem_DEL(tmp);
|
||
return(rtn);
|
||
}
|
||
|
||
static PyObject *
|
||
rotorobj_decrypt_more(Rotorobj *self, PyObject *args)
|
||
{
|
||
char *string = NULL;
|
||
int len = 0;
|
||
PyObject *rtn = NULL;
|
||
char *tmp;
|
||
|
||
if (!PyArg_ParseTuple(args, "s#:decrypt_more", &string, &len))
|
||
return NULL;
|
||
if (!(tmp = PyMem_NEW(char, len+5))) {
|
||
PyErr_NoMemory();
|
||
return NULL;
|
||
}
|
||
memset(tmp, '\0', len+1);
|
||
memcpy(tmp, string, len);
|
||
RTR_d_region(self, (unsigned char *)tmp, len, FALSE);
|
||
rtn = PyString_FromStringAndSize(tmp, len);
|
||
PyMem_DEL(tmp);
|
||
return(rtn);
|
||
}
|
||
|
||
static PyObject *
|
||
rotorobj_setkey(Rotorobj *self, PyObject *args)
|
||
{
|
||
char *key;
|
||
|
||
if (!PyArg_ParseTuple(args, "s:setkey", &key))
|
||
return NULL;
|
||
|
||
set_key(self, key);
|
||
Py_INCREF(Py_None);
|
||
return Py_None;
|
||
}
|
||
|
||
static struct PyMethodDef
|
||
rotorobj_methods[] = {
|
||
{"encrypt", (PyCFunction)rotorobj_encrypt, METH_VARARGS},
|
||
{"encryptmore", (PyCFunction)rotorobj_encrypt_more, METH_VARARGS},
|
||
{"decrypt", (PyCFunction)rotorobj_decrypt, METH_VARARGS},
|
||
{"decryptmore", (PyCFunction)rotorobj_decrypt_more, METH_VARARGS},
|
||
{"setkey", (PyCFunction)rotorobj_setkey, METH_VARARGS},
|
||
{NULL, NULL} /* sentinel */
|
||
};
|
||
|
||
|
||
/* Return a rotor object's named attribute. */
|
||
static PyObject *
|
||
rotorobj_getattr(Rotorobj *s, char *name)
|
||
{
|
||
return Py_FindMethod(rotorobj_methods, (PyObject*)s, name);
|
||
}
|
||
|
||
|
||
static PyTypeObject Rotor_Type = {
|
||
PyObject_HEAD_INIT(NULL)
|
||
0, /*ob_size*/
|
||
"rotor.rotor", /*tp_name*/
|
||
sizeof(Rotorobj), /*tp_size*/
|
||
0, /*tp_itemsize*/
|
||
/* methods */
|
||
(destructor)rotor_dealloc, /*tp_dealloc*/
|
||
0, /*tp_print*/
|
||
(getattrfunc)rotorobj_getattr, /*tp_getattr*/
|
||
0, /*tp_setattr*/
|
||
0, /*tp_compare*/
|
||
0, /*tp_repr*/
|
||
0, /*tp_hash*/
|
||
};
|
||
|
||
|
||
static PyObject *
|
||
rotor_rotor(PyObject *self, PyObject *args)
|
||
{
|
||
Rotorobj *r;
|
||
char *string;
|
||
int num_rotors = 6;
|
||
|
||
if (!PyArg_ParseTuple(args, "s|i:newrotor", &string, &num_rotors))
|
||
return NULL;
|
||
|
||
r = rotorobj_new(num_rotors, string);
|
||
return (PyObject *)r;
|
||
}
|
||
|
||
|
||
|
||
static struct PyMethodDef
|
||
rotor_methods[] = {
|
||
{"newrotor", rotor_rotor, METH_VARARGS},
|
||
{NULL, NULL} /* sentinel */
|
||
};
|
||
|
||
|
||
DL_EXPORT(void)
|
||
initrotor(void)
|
||
{
|
||
Rotor_Type.ob_type = &PyType_Type;
|
||
(void)Py_InitModule("rotor", rotor_methods);
|
||
}
|