diff --git a/research/security.mdwn b/research/security.mdwn
index b03603c47a0861ab8798dd04b86691758e222013..d2eefc8b867ebab02426ac06a766c8af31ac9390 100644
--- a/research/security.mdwn
+++ b/research/security.mdwn
@@ -25,5 +25,6 @@ Research and development in security:
     http://www.slideshare.net/idsecconf/countermeasure-against-timing-attack-on-ssh-using-random-delay
     http://www.scribd.com/doc/59628153/Timing-Analysis-of-Keystrokes-and-Timing-Attacks-on-SSH-Revisited
 * https://shodan.io
+* https://censys.io
 * https://keybase.io
 * https://github.com/shadowsocks/shadowsocks-go