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-rw-r--r--Modules/rotormodule.c280
1 files changed, 43 insertions, 237 deletions
diff --git a/Modules/rotormodule.c b/Modules/rotormodule.c
index 1985e4c..6ead93c 100644
--- a/Modules/rotormodule.c
+++ b/Modules/rotormodule.c
@@ -79,9 +79,8 @@ staticforward PyTypeObject Rotor_Type;
#define is_rotor(v) ((v)->ob_type == &Rotor_Type)
-/*
- This defines the necessary routines to manage rotor objects
-*/
+
+/* This defines the necessary routines to manage rotor objects */
static void
set_seed(r)
@@ -135,9 +134,7 @@ r_rand(r, s)
Rotorobj *r;
short s;
{
- /*short tmp = (short)((int)(r_random(r) * (float)32768.0) % 32768);*/
- short tmp = (short)((short)(r_random(r) * (float)s) % s);
- return tmp;
+ return (short)((short)(r_random(r) * (float)s) % s);
}
static void
@@ -145,35 +142,18 @@ set_key(r, key)
Rotorobj *r;
char *key;
{
-#ifdef BUGGY_CODE_BW_COMPAT
- /* See comments below */
- int k1=995, k2=576, k3=767, k4=671, k5=463;
-#else
unsigned long k1=995, k2=576, k3=767, k4=671, k5=463;
-#endif
int i;
int len = strlen(key);
+
for (i = 0; i < len; i++) {
-#ifdef BUGGY_CODE_BW_COMPAT
- /* This is the code as it was originally released.
- It causes warnings on many systems and can generate
- different results as well. If you have files
- encrypted using an older version you may want to
- #define BUGGY_CODE_BW_COMPAT so as to be able to
- decrypt them... */
- k1 = (((k1<<3 | k1<<-13) + key[i]) & 65535);
- k2 = (((k2<<3 | k2<<-13) ^ key[i]) & 65535);
- k3 = (((k3<<3 | k3<<-13) - key[i]) & 65535);
- k4 = ((key[i] - (k4<<3 | k4<<-13)) & 65535);
- k5 = (((k5<<3 | k5<<-13) ^ ~key[i]) & 65535);
-#else
- /* This code should be more portable */
- k1 = (((k1<<3 | k1>>13) + key[i]) & 65535);
- k2 = (((k2<<3 | k2>>13) ^ key[i]) & 65535);
- k3 = (((k3<<3 | k3>>13) - key[i]) & 65535);
- k4 = ((key[i] - (k4<<3 | k4>>13)) & 65535);
- k5 = (((k5<<3 | k5>>13) ^ ~key[i]) & 65535);
-#endif
+ 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);
@@ -184,6 +164,8 @@ set_key(r, key)
set_seed(r);
}
+
+
/* These define the interface to a rotor object */
static Rotorobj *
rotorobj_new(num_rotors, key)
@@ -226,10 +208,11 @@ rotorobj_new(num_rotors, key)
return (Rotorobj*)PyErr_NoMemory();
}
+
/* These routines impliment the rotor itself */
-/* Here is a fairly sofisticated {en,de}cryption system. It is based
- on the idea of a "rotor" machine. A bunch of rotors, each with a
+/* 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.
@@ -248,16 +231,17 @@ rotorobj_new(num_rotors, key)
encryption routine.
j'
-*/
-/*(defun RTR-make-id-rotor (rotor)
- "Set ROTOR to the identity permutation"
- (let ((j 0))
- (while (< j RTR-size)
- (aset rotor j j)
- (setq j (+ 1 j)))
- rotor))
-*/
+ */
+
+/* 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(r, rtr)
Rotorobj *r;
@@ -271,18 +255,7 @@ RTR_make_id_rotor(r, rtr)
}
-/*(defvar RTR-e-rotors
- (let ((rv (make-vector RTR-number-of-rotors 0))
- (i 0)
- tr)
- (while (< i RTR-number-of-rotors)
- (setq tr (make-vector RTR-size 0))
- (RTR-make-id-rotor tr)
- (aset rv i tr)
- (setq i (+ 1 i)))
- rv)
- "The current set of encryption rotors")
-*/
+/* The current set of encryption rotors */
static void
RTR_e_rotors(r)
Rotorobj *r;
@@ -293,21 +266,7 @@ RTR_e_rotors(r)
}
}
-/*(defvar RTR-d-rotors
- (let ((rv (make-vector RTR-number-of-rotors 0))
- (i 0)
- tr)
- (while (< i RTR-number-of-rotors)
- (setq tr (make-vector RTR-size 0))
- (setq j 0)
- (while (< j RTR-size)
- (aset tr j j)
- (setq j (+ 1 j)))
- (aset rv i tr)
- (setq i (+ 1 i)))
- rv)
- "The current set of decryption rotors")
-*/
+/* The current set of decryption rotors */
static void
RTR_d_rotors(r)
Rotorobj *r;
@@ -320,9 +279,7 @@ RTR_d_rotors(r)
}
}
-/*(defvar RTR-positions (make-vector RTR-number-of-rotors 1)
- "The positions of the rotors at this time")
-*/
+/* The positions of the rotors at this time */
static void
RTR_positions(r)
Rotorobj *r;
@@ -333,9 +290,7 @@ RTR_positions(r)
}
}
-/*(defvar RTR-advances (make-vector RTR-number-of-rotors 1)
- "The number of positions to advance the rotors at a time")
-*/
+/* The number of positions to advance the rotors at a time */
static void
RTR_advances(r)
Rotorobj *r;
@@ -346,22 +301,9 @@ RTR_advances(r)
}
}
-/*(defun RTR-permute-rotor (e d)
- "Permute the E rotor, and make the D rotor its inverse"
- ;; see Knuth for explaination of algorithm.
- (RTR-make-id-rotor e)
- (let ((i RTR-size)
- q j)
- (while (<= 2 i)
- (setq q (fair16 i)) ; a little tricky, decrement here
- (setq i (- i 1)) ; since we have origin 0 array's
- (setq j (aref e q))
- (aset e q (aref e i))
- (aset e i j)
- (aset d j i))
- (aset e 0 (aref e 0)) ; don't forget e[0] and d[0]
- (aset d (aref e 0) 0)))
-*/
+/* Permute the E rotor, and make the D rotor its inverse
+ * see Knuth for explanation of algorithm.
+ */
static void
RTR_permute_rotor(r, e, d)
Rotorobj *r;
@@ -384,19 +326,9 @@ RTR_permute_rotor(r, e, d)
d[(e[0])] = (unsigned char)0;
}
-/*(defun RTR-init (key)
- "Given KEY (a list of 5 16 bit numbers), initialize the rotor machine.
-Set the advancement, position, and permutation of the rotors"
- (R16-set-state key)
- (let (i)
- (setq i 0)
- (while (< i RTR-number-of-rotors)
- (aset RTR-positions i (fair16 RTR-size))
- (aset RTR-advances i (+ 1 (* 2 (fair16 (/ RTR-size 2)))))
- (message "Initializing rotor %d..." i)
- (RTR-permute-rotor (aref RTR-e-rotors i) (aref RTR-d-rotors i))
- (setq i (+ 1 i)))))
-*/
+/* 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(r)
Rotorobj *r;
@@ -417,28 +349,7 @@ RTR_init(r)
r->isinited = TRUE;
}
-/*(defun RTR-advance ()
- "Change the RTR-positions vector, using the RTR-advances vector"
- (let ((i 0)
- (temp 0))
- (if RTR-size-mask
- (while (< i RTR-number-of-rotors)
- (setq temp (+ (aref RTR-positions i) (aref RTR-advances i)))
- (aset RTR-positions i (logand temp RTR-size-mask))
- (if (and (>= temp RTR-size)
- (< i (- RTR-number-of-rotors 1)))
- (aset RTR-positions (+ i 1)
- (+ 1 (aref RTR-positions (+ i 1)))))
- (setq i (+ i 1)))
- (while (< i RTR-number-of-rotors)
- (setq temp (+ (aref RTR-positions i) (aref RTR-advances i)))
- (aset RTR-positions i (% temp RTR-size))
- (if (and (>= temp RTR-size)
- (< i (- RTR-number-of-rotors 1)))
- (aset RTR-positions (+ i 1)
- (+ 1 (aref RTR-positions (+ i 1)))))
- (setq i (+ i 1))))))
-*/
+/* Change the RTR-positions vector, using the RTR-advances vector */
static void
RTR_advance(r)
Rotorobj *r;
@@ -465,25 +376,7 @@ RTR_advance(r)
}
}
-/*(defun RTR-e-char (p)
- "Encrypt the character P with the current rotor machine"
- (let ((i 0))
- (if RTR-size-mask
- (while (< i RTR-number-of-rotors)
- (setq p (aref (aref RTR-e-rotors i)
- (logand (logxor (aref RTR-positions i)
- p)
- RTR-size-mask)))
- (setq i (+ 1 i)))
- (while (< i RTR-number-of-rotors)
- (setq p (aref (aref RTR-e-rotors i)
- (% (logxor (aref RTR-positions i)
- p)
- RTR-size)))
- (setq i (+ 1 i))))
- (RTR-advance)
- p))
-*/
+/* Encrypt the character P with the current rotor machine */
static unsigned char
RTR_e_char(r, p)
Rotorobj *r;
@@ -510,25 +403,7 @@ RTR_e_char(r, p)
return ((unsigned char)tp);
}
-/*(defun RTR-d-char (c)
- "Decrypt the character C with the current rotor machine"
- (let ((i (- RTR-number-of-rotors 1)))
- (if RTR-size-mask
- (while (<= 0 i)
- (setq c (logand (logxor (aref RTR-positions i)
- (aref (aref RTR-d-rotors i)
- c))
- RTR-size-mask))
- (setq i (- i 1)))
- (while (<= 0 i)
- (setq c (% (logxor (aref RTR-positions i)
- (aref (aref RTR-d-rotors i)
- c))
- RTR-size))
- (setq i (- i 1))))
- (RTR-advance)
- c))
-*/
+/* Decrypt the character C with the current rotor machine */
static unsigned char
RTR_d_char(r, c)
Rotorobj *r;
@@ -555,18 +430,7 @@ RTR_d_char(r, c)
return(tc);
}
-/*(defun RTR-e-region (beg end key)
- "Perform a rotor encryption of the region from BEG to END by KEY"
- (save-excursion
- (let ((tenth (/ (- end beg) 10)))
- (RTR-init key)
- (goto-char beg)
- ;; ### make it stop evry 10% or so to tell us
- (while (< (point) end)
- (let ((fc (following-char)))
- (insert-char (RTR-e-char fc) 1)
- (delete-char 1))))))
-*/
+/* Perform a rotor encryption of the region from BEG to END by KEY */
static void
RTR_e_region(r, beg, len, doinit)
Rotorobj *r;
@@ -582,17 +446,7 @@ RTR_e_region(r, beg, len, doinit)
}
}
-/*(defun RTR-d-region (beg end key)
- "Perform a rotor decryption of the region from BEG to END by KEY"
- (save-excursion
- (progn
- (RTR-init key)
- (goto-char beg)
- (while (< (point) end)
- (let ((fc (following-char)))
- (insert-char (RTR-d-char fc) 1)
- (delete-char 1))))))
-*/
+/* Perform a rotor decryption of the region from BEG to END by KEY */
static void
RTR_d_region(r, beg, len, doinit)
Rotorobj *r;
@@ -609,52 +463,8 @@ RTR_d_region(r, beg, len, doinit)
}
-/*(defun RTR-key-string-to-ints (key)
- "Convert a string into a list of 4 numbers"
- (let ((k1 995)
- (k2 576)
- (k3 767)
- (k4 671)
- (k5 463)
- (i 0))
- (while (< i (length key))
- (setq k1 (logand (+ (logior (lsh k1 3) (lsh k1 -13)) (aref key i)) 65535))
- (setq k2 (logand (logxor (logior (lsh k2 3) (lsh k2 -13)) (aref key i)) 65535))
- (setq k3 (logand (- (logior (lsh k3 3) (lsh k3 -13)) (aref key i)) 65535))
- (setq k4 (logand (- (aref key i) (logior (lsh k4 3) (lsh k4 -13))) 65535))
- (setq k5 (logand (logxor (logior (lsh k5 3) (lsh k5 -13)) (lognot (aref key i))) 65535))
- (setq i (+ i 1)))
- (list k1 (logior 1 k2) k3 k4 k5)))*/
-/* This is done in set_key() above */
-
-#if 0
-/*(defun encrypt-region (beg end key)
- "Interactivly encrypt the region"
- (interactive "r\nsKey:")
- (RTR-e-region beg end (RTR-key-string-to-ints key)))*/
-static void encrypt_region(r, region, len)
- Rotorobj *r;
- unsigned char *region;
- int len;
-{
- RTR_e_region(r,region,len,TRUE);
-}
-
-/*(defun decrypt-region (beg end key)
- "Interactivly decrypt the region"
- (interactive "r\nsKey:")
- (RTR-d-region beg end (RTR-key-string-to-ints key)))*/
-static void decrypt_region(r, region, len)
- Rotorobj *r;
- unsigned char *region;
- int len;
-{
- RTR_d_region(r,region,len,TRUE);
-}
-#endif /* 0 */
-
+
/* Rotor methods */
-
static void
rotor_dealloc(xp)
Rotorobj *xp;
@@ -833,6 +643,7 @@ rotor_rotor(self, args)
}
+
static struct PyMethodDef
rotor_methods[] = {
{"newrotor", rotor_rotor, 1},
@@ -840,11 +651,6 @@ rotor_methods[] = {
};
-/* Initialize this module.
- This is called when the first 'import rotor' is done,
- via a table in config.c, if config.c is compiled with USE_ROTOR
- defined. */
-
void
initrotor()
{
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