diff --git a/include/protocols.h b/include/protocols.h
index de38e1aea..519172af6 100644
--- a/include/protocols.h
+++ b/include/protocols.h
@@ -385,6 +385,7 @@ ISO 7816-4 Basic interindustry commands. For command APDU's.
 #define MFDES_CHANGE_KEY                0xc4
 #define MFDES_GET_KEY_VERSION           0x64
 #define MFDES_AUTHENTICATION_FRAME      0xAF
+#define MFDES_READSIG                   0x3C
 
 // LEGIC Commands
 #define LEGIC_MIM_22                    0x0D