diff --git a/metropolis/proto/api/management.proto b/metropolis/proto/api/management.proto
index 9f0e646..44db0c5 100644
--- a/metropolis/proto/api/management.proto
+++ b/metropolis/proto/api/management.proto
@@ -45,6 +45,6 @@
     // cluster that can be used to dial the cluster's services.
     metropolis.proto.common.ClusterDirectory cluster_directory = 1;
 
-    // ca_public_key is the Ed25519 public key of the CA of the cluster.
-    bytes ca_public_key = 2;
+    // ca_certificate is the x509 DER encoded CA certificate of the cluster.
+    bytes ca_certificate = 2;
 }