set3, challenge 22 completed

1 files changed, 32 insertions, 0 deletions

diff --git a/lib/lib3.c b/lib/lib3.c
index 43f3ec6..adea72e 100644
--- a/lib/lib3.c
+++ b/lib/lib3.c
@@ -129,3 +129,35 @@ int mt_19937()
 
 	return (y & 0xFFFFFFFF);
 }
+
+int mt_19937_timestamp_orcale()
+{
+	sleep(random_number_between(40,1000));
+
+	unsigned int seed = time(NULL);
+	printf("timestamp orcale seed: %u\n", seed);
+	mt_19937_seed(seed);
+
+	sleep(random_number_between(40,1000));
+
+	return  mt_19937();
+}
+/***
+  * is there a more clever way to do this than brute force?
+  *
+  **/
+void mt_19937_brute_force_timestamp()
+{
+	unsigned int start = time(NULL);
+	int rnd = mt_19937_timestamp_orcale();
+	unsigned int stop = time(NULL);
+	unsigned int i;
+	// try every seed between start and stop
+	for(i=start;start<=stop;i++) {
+		mt_19937_seed(i);
+		if (rnd == mt_19937()) {
+			printf("found seed: %u\n", i);
+			break;
+		}
+	}
+}