Made day4 C. Yay!

1 files changed, 53 insertions, 0 deletions

diff --git a/day4.c b/day4.c
new file mode 100644
index 0000000..ae3fb94
--- /dev/null
+++ b/day4.c
@@ -0,0 +1,53 @@
+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>

+#include <openssl/md5.h>

+

+unsigned char* secret = "iwrupvqb";

+unsigned char* target = "000000";

+unsigned char result[MD5_DIGEST_LENGTH];

+

+void hash(int i) {

+  char num[12];

+  sprintf(num, "%d", i);

+  char str[22] = "";

+  strcat(str, secret);

+  strcat(str, num);

+

+  MD5(str, strlen(str), result);

+}

+

+int tohex() {

+  int i, dg = 0;

+  for(i = 0; i < 4; i++) {

+    dg <<= 8;

+    dg += result[i];

+  }

+  return dg;

+}

+

+int check(int len) {

+  unsigned char str[8];

+  int dg = tohex();

+  sprintf(str, "%08x", dg);

+  return strncmp(str, target, len) == 0;

+}

+

+int main() {

+  int i = 1, got5 = 0, got6 = 0;

+

+  while(!(got5 && got6)) {

+    hash(i);

+    if(!got5 && check(5)) {

+      got5 = 1;

+      printf("Lowest number for 5-zeroes hash: %d\n", i);

+    }

+    if(!got6 && check(6)) {

+      got6 = 1;

+      printf("Lowest number for 6-zeroes hash: %d\n", i);

+    }

+    i++;

+  }

+

+  return 0;

+}