diff --git a/test/functional/WorkerUnityCourseTest.php b/test/functional/WorkerUnityCourseTest.php
index f0d522d25..fce752fa4 100644
--- a/test/functional/WorkerUnityCourseTest.php
+++ b/test/functional/WorkerUnityCourseTest.php
@@ -2,9 +2,11 @@
 
 class WorkerUnityCourseTest extends UnityWebPortalTestCase
 {
+    private static string $course_id = "cs124";
+    private static string $course_org = "org1_test";
     private static string $course_owner_uid = "cs124_org1_test";
     private static string $course_gid = "pi_cs124_org1_test";
-    private static array $course_owner_name = ["cs124", "Fall 2025"];
+    private static string $course_semester = "Fall 2025";
     private static string $test1_manager_uid = "user2_org1_test";
     private static array $test2_manager_uids = ["user2_org1_test", "user1_org1_test"];
     private static string $test2_manager_uids_str = " user2_org1_test , user1_org1_test , ,,, user2_org1_test ";
@@ -23,9 +25,9 @@ public function testCreateCourse()
         $this->assertFalse($pi_group_entry->exists());
         $this->assertFalse($owner_user_entry->exists());
         $stdin_file = writeLinesToTmpFile([
-            self::$course_owner_name[0],
-            self::$course_owner_name[1],
-            self::$course_owner_uid,
+            self::$course_id,
+            self::$course_semester,
+            self::$course_org,
             self::$test1_manager_uid,
         ]);
         $stdin_file_path = getPathFromFileHandle($stdin_file);
@@ -62,9 +64,9 @@ public function testCreateCourseMultipleManagers()
         $this->assertFalse($pi_group_entry->exists());
         $this->assertFalse($owner_user_entry->exists());
         $stdin_file = writeLinesToTmpFile([
-            self::$course_owner_name[0],
-            self::$course_owner_name[1],
-            self::$course_owner_uid,
+            self::$course_id,
+            self::$course_semester,
+            self::$course_org,
             self::$test2_manager_uids_str,
         ]);
         $stdin_file_path = getPathFromFileHandle($stdin_file);
diff --git a/workers/unity-course.php b/workers/unity-course.php
index 19653d630..d2157310e 100755
--- a/workers/unity-course.php
+++ b/workers/unity-course.php
@@ -6,14 +6,6 @@
 use UnityWebPortal\lib\UnityOrg;
 use UnityWebPortal\lib\UserFlag;
 
-function cn2org($cn)
-{
-    $matches = [];
-    _preg_match("/.*_([^_]+_[^_]+)$/", $cn, $matches);
-    assert(count($matches) == 2, "failed to extract org from cn: '$cn'");
-    return $matches[1];
-}
-
 // if array is length 1 then replace it with its one element
 function flatten_attributes(array $attributes): array
 {
@@ -32,17 +24,21 @@ function parse_comma_delimited_list(string $input): array
 }
 
 $givenName = trim(readline("Enter the course ID (example: CS123): "));
+if (!_preg_match("/^[a-zA-Z0-9_-]+$/", $givenName)) {
+    _die("error: course ID '$givenName' contains invalid characters", 1);
+}
 $sn = trim(readline("Enter the year and semester of the course (example: Fall 2025): "));
-$cn = strtolower(
-    trim(readline("Please enter the cn to be used for the course (example: cs123_umass_edu): ")),
-);
+$org_gid = strtolower(trim(readline("Please enter the organization (example: umass_edu): ")));
+if (!_preg_match("/^[a-z0-9_]+$/", $org_gid)) {
+    _die("error: organization '$org_gid' contains invalid characters", 1);
+}
+$cn = implode("_", [strtolower($givenName), $org_gid]);
 $manager_uids = parse_comma_delimited_list(
     readline("Enter the UID(s) of the group manager(s) (example: simonleary_umass_edu,bryank_uri_edu): ")
 );
 if (count($manager_uids) === 0) {
     _die("at least one group manager UID is required", 1);
 }
-$org_gid = cn2org($cn);
 
 $managers = [];
 foreach ($manager_uids as $manager_uid) {