diff --git a/sim/src/caps.rs b/sim/src/caps.rs
index f823b99..edffd0c 100644
--- a/sim/src/caps.rs
+++ b/sim/src/caps.rs
@@ -23,6 +23,7 @@
     EncEc256             = (1 << 10),
     SwapUsingMove        = (1 << 11),
     DowngradePrevention  = (1 << 12),
+    EncX25519            = (1 << 13),
 }
 
 impl Caps {