find RC632 key patters in files

diff --git a/mifare_rc632_find_key.c b/mifare_rc632_find_key.c
new file mode 100644 (file)
index 0000000..730e65f
--- /dev/null
+++ b/mifare_rc632_find_key.c
@@ -0,0 +1,69 @@
+/*
+
+Find rc632 keys encoded as 12 bytes for flash writing
+Dobrica Pavlinusic <dpavlin@rot13.org> 2014-01-22
+
+compile with:
+
+gcc -o mifare_rc632_find_key mifare_rc632_find_key.c
+
+try it out:
+
+mifare_rc632_find_key some_binary_file_with_keys
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+int main ( int argc, char *argv[] ) {
+       FILE *fd;
+       char *filename;
+
+       filename = argv[1];
+
+       fd = fopen(filename,"rb");
+       if ( fd == NULL ) {
+               printf("error opening %s", filename);
+               exit(1);
+       }
+
+       fseek(fd, 0, SEEK_END);
+       long size = ftell(fd);
+       fseek(fd, 0, SEEK_SET);
+
+       char *str = malloc( size + 1 );
+       fread(str, size, 1, fd);
+       fclose(fd);
+
+       int keys_found = 0;
+
+       int i;
+       for( i = 0; i <= size; i++ ) {
+
+               bool found = true;
+               int j;
+               char key[12];
+
+               for ( j = 0; j <= 11; j++ ) {
+                       char c = str[i + j];
+
+                       if ( ( ( ( c & 0xf0 ) ^ 0xf0 ) >> 4 ) != ( c & 0x0f ) ) {
+                               found = false;
+                               break;
+                       }
+                       key[j] = c;
+               }
+               if ( found ) {
+                       printf("%08x: ", i);
+                       for( j = 0; j <= 11; j++ ) {
+                               printf("%01x", (unsigned char)key[j] & 0x0f);
+                       }
+                       printf(" %s\n", filename);
+                       keys_found++;
+               }
+
+       }
+}
+