diff --git a/os/auth.c b/os/auth.c
index a22980efd..fd1f3f409 100644
--- a/os/auth.c
+++ b/os/auth.c
@@ -64,7 +64,7 @@ struct protocol {
 
 static struct protocol protocols[] = {
     {
-        .name = "MIT-MAGIC-COOKIE-1",
+        .name = XAUTH_PROTO_MIT,
         .Add = MitAddCookie,
         .Check = MitCheckCookie,
         .Reset = MitResetCookie,
@@ -74,7 +74,7 @@ static struct protocol protocols[] = {
     },
 #ifdef HASXDMAUTH
     {
-        .name = "XDM-AUTHORIZATION-1",
+        .name = XAUTH_PROTO_XDM,
         .Add = XdmAddCookie,
         .Check = XdmCheckCookie,
         .Reset = XdmResetCookie,
diff --git a/os/auth.h b/os/auth.h
index 5d23e9ada..b626828c8 100644
--- a/os/auth.h
+++ b/os/auth.h
@@ -5,6 +5,9 @@
 
 #include "dix.h"
 
+#define XAUTH_PROTO_MIT "MIT-MAGIC-COOKIE-1"
+#define XAUTH_PROTO_XDM "XDM-AUTHORIZATION-1"
+
 #define AuthInitArgs void
 typedef void (*AuthInitFunc) (AuthInitArgs);