crypto1_bs.diff

diff --git a/libnfc_crypto1_crack.c b/libnfc_crypto1_crack.c
index 8a53f64..21feed2 100644
--- a/libnfc_crypto1_crack.c
+++ b/libnfc_crypto1_crack.c
@@ -713,6 +713,17 @@ int main (int argc, const char * argv[]) {
         return 1;
     } else {
         printf("Found key: %012"PRIx64"\n", found_key);
+        if (argc==7) {
+            FILE *fpKey = NULL;
+            fpKey = fopen(argv[6], "a");
+            if (fpKey) {
+                fprintf(fpKey, "%012llx\r\n", found_key);
+                fclose(fpKey);
+            } else {
+                fprintf(stderr, "Cannot open: %s, exiting\n", argv[6]);
+                return 1;
+            }
+        }
     }
     printf("Tested %zu states\n", total_states_tested);