diff --git a/problem-sets-competitive-programming.md b/problem-sets-competitive-programming.md
index 232773746..ee0096f08 100644
--- a/problem-sets-competitive-programming.md
+++ b/problem-sets-competitive-programming.md
@@ -39,6 +39,7 @@
 
 ### Information security
 
+* [ångstromCTF](https://angstromctf.com)
 * [CTFtime](https://ctftime.org)