* Paypal decoder. 64% efficiency.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/pwntcha/trunk@456 92316355-f0b4-4df1-b90c-862c8a59935f

src/Makefile.am

@@ -10,6 +10,7 @@ pwntcha_SOURCES = \
     authimage.c \
     clubic.c \
     linuxfr.c \
+    paypal.c \
     phpbb.c \
     scode.c \
     slashdot.c \

src/common.h

@@ -41,6 +41,7 @@ void dprintf(const char *fmt, ...);
 char *decode_authimage(struct image *img);
 char *decode_clubic(struct image *img);
 char *decode_linuxfr(struct image *img);
+char *decode_paypal(struct image *img);
 char *decode_phpbb(struct image *img);
 char *decode_scode(struct image *img);
 char *decode_slashdot(struct image *img);

src/main.c

@@ -138,6 +138,8 @@ int main(int argc, char *argv[])
             result = decode_clubic(img);
         else if(!strcmp(mode, "linuxfr"))
             result = decode_linuxfr(img);
+        else if(!strcmp(mode, "paypal"))
+            result = decode_paypal(img);
         else if(!strcmp(mode, "phpbb"))
             result = decode_phpbb(img);
         else if(!strcmp(mode, "scode"))
@@ -160,6 +162,11 @@ int main(int argc, char *argv[])
                 dprintf("autodetected linuxfr captcha\n");
                 result = decode_linuxfr(img);
             }
+            else if(img->width == 208 && img->height == 26)
+            {
+                dprintf("autodetected Paypal captcha\n");
+                result = decode_paypal(img);
+            }
             else if(img->width == 320 && img->height == 50)
             {
                 dprintf("autodetected phpBB captcha\n");

src/paypal.c

@@ -0,0 +1,135 @@
+/*
+ * paypal.c: decode Paypal captchas
+ * $Id$
+ *
+ * Copyright: (c) 2005 Sam Hocevar <sam@zoy.org>
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the Do What The Fuck You Want To
+ *   Public License as published by Banlu Kemiyatorn. See
+ *   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+
+#include "config.h"
+#include "common.h"
+
+static void find_glyphs(struct image *img);
+
+/* Our macros */
+char *result;
+
+/* Main function */
+char *decode_paypal(struct image *img)
+{
+    struct image *tmp;
+
+    /* paypal captchas have 8 characters */
+    result = malloc(9 * sizeof(char));
+    strcpy(result, "        ");
+
+    tmp = image_dup(img);
+    find_glyphs(tmp);
+
+    image_free(tmp);
+
+    return result;
+}
+
+static void find_glyphs(struct image *img)
+{
+#define DELTA 2
+#define FONTS 2
+    static struct font *fonts[FONTS];
+    static char *files[] =
+    {
+        "font_stencil_23_AZ.bmp", "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+        "font_stencil_24_AZ.bmp", "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ",
+    };
+    int x, y, i = 0, f;
+    int r, g, b;
+    int xmin, xmax, ymin, ymax, startx = 0, cur = 0;
+    int bestdist, bestfont, bestx, besty, bestch;
+
+    for(f = 0; f < FONTS; f++)
+    {
+        if(!fonts[f])
+        {
+            fonts[f] = font_load_variable(files[f * 2], files[f * 2 + 1]);
+            if(!fonts[f])
+                exit(1);
+        }
+    }
+
+    while(cur < 8)
+    {
+        /* Try to find 1st letter */
+        bestdist = INT_MAX;
+        for(f = 0; f < FONTS; f++) for(i = 0; i < fonts[f]->size; i++)
+        {
+            int localmin = INT_MAX, localx, localy;
+            xmin = fonts[f]->glyphs[i].xmin - DELTA;
+            ymin = fonts[f]->glyphs[i].ymin;
+            xmax = fonts[f]->glyphs[i].xmax + DELTA;
+            ymax = fonts[f]->glyphs[i].ymax;
+            for(y = -3; y < 1; y++)
+            {
+                for(x = startx; x < startx + 15; x++)
+                {
+                    int z, t, dist;
+                    dist = 0;
+                    for(t = 0; t < ymax - ymin; t++)
+                        for(z = 0; z < xmax - xmin; z++)
+                        {
+                            int r2;
+                            getgray(fonts[f]->img, xmin + z, ymin + t, &r);
+                            getgray(img, x + z, y + t, &r2);
+                            if(r < r2)
+                                dist += abs(r - r2);
+                            else
+                                dist += abs(r - r2) * 3 / 4;
+                        }
+                    //dist = dist * 128 / fonts[f]->glyphs[i].count;
+                    dist  = dist * 1024 / (xmax - xmin - 2 * DELTA);
+                    if(dist < localmin)
+                    {
+                        localmin = dist;
+                        localx = x;
+                        localy = y;
+                    }
+                }
+            }
+            if(localmin < bestdist)
+            {
+                bestdist = localmin;
+                bestfont = f;
+                bestx = localx;
+                besty = localy;
+                bestch = i;
+            }
+        }
+
+        /* Print min glyph */
+#if 0
+        xmin = fonts[bestfont]->glyphs[bestch].xmin - DELTA;
+        ymin = fonts[bestfont]->glyphs[bestch].ymin;
+        xmax = fonts[bestfont]->glyphs[bestch].xmax + DELTA;
+        ymax = fonts[bestfont]->glyphs[bestch].ymax;
+        for(y = 0; y < ymax - ymin; y++)
+            for(x = 0; x < xmax - xmin; x++)
+            {
+                getpixel(fonts[bestfont]->img, xmin + x, ymin + y, &r, &g, &b);
+                if(r > 128)
+                    continue;
+                setpixel(img, bestx + x, besty + y, r, g, b);
+            }
+#endif
+
+        startx = bestx + xmax - xmin;
+        result[cur++] = fonts[bestfont]->glyphs[bestch].c;
+    }
+}
+