diff --git a/lib/hx509/hx509_err.et b/lib/hx509/hx509_err.et
index 73fdf796e..251115359 100644
--- a/lib/hx509/hx509_err.et
+++ b/lib/hx509/hx509_err.et
@@ -24,6 +24,7 @@ error_code VERIFY_CONSTRAINTS,	"Error verifing constraints"
 error_code RANGE,		"Number too large"
 error_code NAME_CONSTRAINT_ERROR, "Error while verifing name constraints"
 error_code PATH_TOO_LONG, "Path is too long, failed to find valid anchor"
+error_code KU_CERT_MISSING, "Required keyusage for this certificate is missing"
 
 index 32
 prefix HX509_CMS