diff --git a/access.lua b/access.lua
index 3964af0..0967eca 100644
--- a/access.lua
+++ b/access.lua
@@ -41,11 +41,11 @@ if ngx.var.host ~= conf["portal_domain"] and ngx.var.request_method == "GET" the
 
         -- Use the `cache` shared table where a username is associated with
         -- a CDA key
-        user = cache:get(cda_key)
+        user = cache:get("CDA|"..cda_key)
         if user then
             hlp.set_auth_cookie(user, ngx.var.host)
             ngx.log(ngx.NOTICE, "Cross-domain authentication: "..user.." connected on "..ngx.var.host)
-            cache:delete(cda_key)
+            cache:delete("CDA|"..cda_key)
         end
 
         uri_args[conf.login_arg] = nil
diff --git a/helpers.lua b/helpers.lua
index 41e8f37..db87a8b 100644
--- a/helpers.lua
+++ b/helpers.lua
@@ -108,7 +108,7 @@ end
 -- Set the Cross-Domain-Authentication key for a specific user
 function set_cda_key()
     local cda_key = random_string()
-    cache:set(cda_key, authUser, 10)
+    cache:set("CDA|"..cda_key, authUser, 10)
     return cda_key
 end