diff --git a/2016/day05.rkt b/2016/day05.rkt
new file mode 100644
index 0000000..3454698
--- /dev/null
+++ b/2016/day05.rkt
@@ -0,0 +1,15 @@
+#lang br
+(require openssl/md5)
+
+(define key "ojvtpuvg")
+
+(let loop ([idx 0][password-cs empty])
+  (cond
+    [(= 8 (length password-cs))
+     (apply string-append (reverse password-cs))]
+    [else
+     (define this-key (format "~a~a" key idx))
+     (define next-hash (md5 (open-input-string this-key)))
+     (if (string-prefix? next-hash "00000")
+         (loop (add1 idx) (cons (substring next-hash 5 6) password-cs))
+         (loop (add1 idx) password-cs))]))