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#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
/* CP mask code */
/* The original CP code was written by Hirotsuna Mizuno and is
* Copyright (c) 1998 Hirotsuna Mizuno <s1041150@u-aizu.ac.jp>
*
* I heavily modified his code.
* as for speed, this algorithm could be improved without end,
* and alternative algorithms might exist that might be several orders
* of magnitude faster.
*/
/* this is faster */
typedef unsigned int UI;
static UI image_width;
static UI image_height;
static u8 *image_data;
static UI transform_width;
static UI transform_height;
static u8 *transform_data;
typedef struct
{
UI dst_x, dst_y;
int mirror;
}
cp_cell;
static UI cp_cells;
static cp_cell *cp_trans;
static int *cp_table;
static UI cp_width;
static UI cp_height;
#define CP_CODE_MAX_LENGTH 16
#define CP_CELL_SIZE 8
#define CP_BPP 3
#define OFFSET_X 0
#define OFFSET_Y 0
/* the maximum size of the transformed image in cells */
#define MAX_SIZE 4
#define MAX_CP_WIDTH 2048
#define src_pixel(x,y,c) image_data [((y)*image_width +(x)) * CP_BPP + (c)]
#define dst_pixel(x,y,c) transform_data [((y)*transform_width+(x)) * CP_BPP + (c)]
static void
load_img (const char *name)
{
FILE *img;
UI image_depth;
if (image_data)
fprintf (stderr, "cannot load more than one image\n");
else
{
img = fopen (name, "rb");
if (img)
{
if (fscanf (img, "P6 ") == EOF)
perror ("no BINARY PPM header detected");
else
{
fscanf (img, "#%*[^\012\015] "); /* comment */
if (fscanf (img, "%u ", &image_width) != 1)
fprintf (stderr, "unable to read image width\n");
else
{
fscanf (img, "#%*[^\012\015] "); /* comment */
if (fscanf (img, "%u ", &image_height) != 1)
fprintf (stderr, "unable to read image height\n");
else
{
fscanf (img, "#%*[^\012\015] "); /* comment */
if (fscanf (img, "%u%*[ \012\015] ", &image_depth) != 1)
fprintf (stderr, "unable to read image depth\n");
else
{
if (image_depth != 255)
fprintf (stderr, "pixel maxval %d (!= 255) is not supported\n", image_depth);
else
{
image_data = (u8 *) malloc (image_width * image_height * CP_BPP);
if (!image_data)
fprintf (stderr, "unable to allocate memory for image\n");
else
{
if (fread (image_data, image_width * image_height * CP_BPP, 1, img) != 1)
fprintf (stderr, "unable to read image data\n");
else
{
/*fprintf (stderr, "read image %dx%d, %d\n", image_width, image_height, image_depth); */
file_path[file_count++] = name;
}
}
}
}
}
}
fclose (img);
}
}
}
}
/* if you are interested, the following code can detect hidden passwords
* stored in CP-masked-JPEG files.
*/
/*
* sorry, the detect code was removed ;)
*/
/*----------------------------------------------------------------------------*/
static u8 cp_key[] =
{
0x10, 0x17, 0x13, 0x15, 0x09, 0x08, 0x0a, 0x14, 0x06, 0x05, 0x16, 0x02, 0x0d,
0x03, 0x01, 0x04, 0x19, 0x0c, 0x0f, 0x0e, 0x12, 0x07, 0x0b, 0x18, 0x11, 0x1a
};
static cp_table_lu1[MAX_CP_WIDTH];
static cp_table_lu2[MAX_CP_WIDTH];
/* this is a bottleneck */
static void
cp_set_pw (u8 * pw, u8 * pw_end)
{
u8 *cursor;
int i, j, x, y, len;
int *table;
cp_cell *trans;
len = pw_end - pw;
for (i = x = y = 0, table = cp_table, trans = cp_trans;
i < cp_cells;
i++)
{
*table++ = -1;
trans->dst_x = x;
trans->dst_y = y;
trans->mirror = 0;
trans++;
if (++x == cp_width)
{
x = 0;
y++;
}
}
x = cp_cells - 1;
y = len + cp_cells % len;
for (i = 0, cursor = pw; i < cp_cells; i++)
{
x = cp_key[*cursor - 'A'] + x + y;
if (++cursor == pw_end)
cursor = pw;
if (x >= cp_cells)
x -= cp_cells;
if (x >= cp_cells)
x -= cp_cells;
while (cp_table[x] != -1)
{
++x;
if (x >= cp_cells)
x = 0;
}
cp_table[x] = i;
y++;
if (++i >= cp_cells)
break;
x = cp_key[*cursor - 'A'] + x + y;
if (++cursor == pw_end)
cursor = pw;
if (x >= cp_cells)
x -= cp_cells;
if (x >= cp_cells)
x -= cp_cells;
while (cp_table[x] != -1)
{
if (x == 0)
x = cp_cells;
x--;
}
cp_table[x] = i;
y++;
}
for (i = 0, j = cp_cells - 1; i < j; i++, j--)
{
cp_trans[cp_table[i]].dst_x = cp_table_lu1[j];
cp_trans[cp_table[i]].dst_y = cp_table_lu2[j];
cp_trans[cp_table[j]].dst_x = cp_table_lu1[i];
cp_trans[cp_table[j]].dst_y = cp_table_lu2[i];
if ((cp_table[i] ^ cp_table[j]) & 1)
{
cp_trans[cp_table[i]].mirror = 1;
cp_trans[cp_table[j]].mirror = 1;
}
}
}
/*----------------------------------------------------------------------------*/
static void
cp_do_mask (void)
{
UI x, y, src_x, src_y;
UI u, v, dst_x, dst_y;
UI xx;
int rot;
cp_cell *cell = cp_trans;
for (y = 0; y < cp_height; ++y)
{
for (x = 0; x < cp_width; ++x)
{
{
u = cell->dst_x;
v = cell->dst_y;
rot = cell->mirror;
cell++;
dst_x = x * CP_CELL_SIZE + OFFSET_X;
dst_y = y * CP_CELL_SIZE + OFFSET_Y;
src_x = u * CP_CELL_SIZE + OFFSET_X;
src_y = v * CP_CELL_SIZE + OFFSET_Y;
}
#define COPY(sx,sy,dx,dy) do { \
u8 *s = &src_pixel (src_x + (sx), src_y + (sy), 0); \
u8 *d = &dst_pixel (dst_x + (dx), dst_y + (dy), 0); \
*d++ = *s++; \
*d++ = *s++; \
*d++ = *s++; \
} while(0)
if (dst_x + CP_CELL_SIZE <= transform_width &&
dst_y + CP_CELL_SIZE <= transform_height)
{
if (rot)
{
/* this is shit */
for (xx = CP_CELL_SIZE - 1; xx--;)
{
COPY (xx + 1, 0, 0, xx + 1);
COPY (0, xx, xx, 0);
COPY (xx, CP_CELL_SIZE - 1, CP_CELL_SIZE - 1, xx);
COPY (CP_CELL_SIZE - 1, xx + 1, xx + 1, CP_CELL_SIZE - 1);
}
}
else
{
for (xx = CP_CELL_SIZE; xx--;)
{
COPY (xx + 1, 0, xx + 1, 0);
COPY (0, xx, 0, xx);
COPY (xx, CP_CELL_SIZE - 1, xx, CP_CELL_SIZE - 1);
COPY (CP_CELL_SIZE - 1, xx + 1, CP_CELL_SIZE - 1, xx + 1);
}
}
}
#undef COPY
}
}
// {FILE *f=fopen("x.ppm","wb"); fprintf (f,"P6 %d %d %d ",transform_width,transform_height,255); fwrite(transform_data,transform_width*transform_height*CP_BPP,1,f); fclose(f); }
}
static void
cp_cleanup (void)
{
if (cp_table)
free (cp_table);
if (cp_trans)
free (cp_trans);
}
static void
init_cpmask (void)
{
UI i;
assert (image_data);
cp_width = image_width / CP_CELL_SIZE;
cp_height = image_height / CP_CELL_SIZE;
cp_cells = cp_width * cp_height;
cp_table = (int *) malloc (sizeof (int) * cp_cells);
cp_trans = (cp_cell *) malloc (sizeof (cp_cell) * cp_cells);
if (cp_width > MAX_CP_WIDTH)
{
printf ("maximum image width in this version is %d\n", MAX_CP_WIDTH * CP_CELL_SIZE);
exit (1);
}
for (i = 0; i < MAX_CP_WIDTH; i++)
{
cp_table_lu1[i] = i % cp_width;
cp_table_lu2[i] = i / cp_width;
}
transform_width = image_width < CP_CELL_SIZE * MAX_SIZE ? image_width : CP_CELL_SIZE * MAX_SIZE;
transform_height = image_height < CP_CELL_SIZE * MAX_SIZE ? image_height : CP_CELL_SIZE * MAX_SIZE;
transform_data = (u8 *) malloc (transform_width * transform_height * CP_BPP);
}
static int
crack_cpmask (gen_func genfunc, callback_func cbfunc)
{
unsigned long minimum = 1 << 31;
unsigned long current;
int changed = -1;
int x, y;
do
{
if (changed >= 4 && verbosity)
printf ("checking pw %s\r", pw), fflush (stdout);
if (changed < 0)
pw_end = pw + strlen (pw);
cp_set_pw (pw, pw_end);
cp_do_mask ();
#define P(x,y,c) (UI)dst_pixel((x),(y),(c))
current = 0;
for (x = CP_CELL_SIZE; x < transform_width; x += CP_CELL_SIZE)
for (y = transform_height; y--;)
{
current += abs (P (x - 1, y, 0) - P (x, y, 0));
current += abs (P (x - 1, y, 1) - P (x, y, 1));
current += abs (P (x - 1, y, 2) - P (x, y, 2));
if (current > minimum)
goto overflow;
}
for (y = CP_CELL_SIZE; y < transform_height && current < minimum; y += CP_CELL_SIZE)
for (x = transform_width; x-- && current < minimum;)
{
current += abs (P (x, y - 1, 0) - P (x, y, 0));
current += abs (P (x, y - 1, 1) - P (x, y, 1));
current += abs (P (x, y - 1, 2) - P (x, y, 2));
if (current > minimum)
goto overflow;
}
#undef P
overflow:
if (current < minimum)
{
char info[80];
minimum = current + 99;
sprintf (info, "badness %ld", current);
if ((changed = cbfunc (pw, info)))
return changed;
}
}
while ((changed = genfunc ()));
return 0;
}
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