diff --git a/draft-ietf-scitt-scrapi.md b/draft-ietf-scitt-scrapi.md
index d4e0e10..0727c25 100644
--- a/draft-ietf-scitt-scrapi.md
+++ b/draft-ietf-scitt-scrapi.md
@@ -68,7 +68,7 @@ informative:
 --- abstract
 
 This document describes a REST API that supports the normative requirements of the SCITT Architecture.
-Optional key discovery and query interfaces are provided to support interoperability with X509 Certificates, alternative methods commonly used to support public key discovery and Artifact Repositories.
+Optional key discovery and query interfaces are provided to support interoperability with X.509 Certificates, alternative methods commonly used to support public key discovery and Artifact Repositories.
 
 --- middle