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