diff --git a/keyserver/src/cron/cron.js b/keyserver/src/cron/cron.js
index 2b83481e3..6540ed0af 100644
--- a/keyserver/src/cron/cron.js
+++ b/keyserver/src/cron/cron.js
@@ -1,107 +1,121 @@
 // @flow
 
 import cluster from 'cluster';
 import schedule from 'node-schedule';
 
 import { backupDB } from './backups.js';
 import { createDailyUpdatesThread } from './daily-updates.js';
 import { updateAndReloadGeoipDB } from './update-geoip-db.js';
+import { updateIdentityReservedUsernames } from './update-identity-reserved-usernames.js';
 import { deleteOrphanedActivity } from '../deleters/activity-deleters.js';
 import { deleteExpiredCookies } from '../deleters/cookie-deleters.js';
 import { deleteOrphanedDays } from '../deleters/day-deleters.js';
 import { deleteOrphanedEntries } from '../deleters/entry-deleters.js';
 import { deleteOrphanedMemberships } from '../deleters/membership-deleters.js';
 import { deleteOrphanedMessages } from '../deleters/message-deleters.js';
 import { deleteOrphanedNotifs } from '../deleters/notif-deleters.js';
 import { deleteOrphanedRevisions } from '../deleters/revision-deleters.js';
 import { deleteOrphanedRoles } from '../deleters/role-deleters.js';
 import {
   deleteOrphanedSessions,
   deleteOldWebSessions,
 } from '../deleters/session-deleters.js';
 import { deleteStaleSIWENonceEntries } from '../deleters/siwe-nonce-deleters.js';
 import { deleteInaccessibleThreads } from '../deleters/thread-deleters.js';
 import { deleteExpiredUpdates } from '../deleters/update-deleters.js';
 import { deleteUnassignedUploads } from '../deleters/upload-deleters.js';
 import { fetchCallUpdateOlmAccount } from '../updaters/olm-account-updater.js';
 import { validateAccountPrekey } from '../utils/olm-utils.js';
 
 if (cluster.isMaster) {
   schedule.scheduleJob(
     '30 3 * * *', // every day at 3:30 AM in the keyserver's timezone
     async () => {
       try {
         // Do everything one at a time to reduce load since we're in no hurry,
         // and since some queries depend on previous ones.
         await deleteExpiredCookies();
         await deleteInaccessibleThreads();
         await deleteOrphanedMemberships();
         await deleteOrphanedDays();
         await deleteOrphanedEntries();
         await deleteOrphanedRevisions();
         await deleteOrphanedRoles();
         await deleteOrphanedMessages();
         await deleteOrphanedActivity();
         await deleteOrphanedNotifs();
         await deleteOrphanedSessions();
         await deleteOldWebSessions();
         await deleteExpiredUpdates();
         await deleteUnassignedUploads();
         await deleteStaleSIWENonceEntries();
       } catch (e) {
         console.warn('encountered error while trying to clean database', e);
       }
     },
   );
   schedule.scheduleJob(
     '0 */4 * * *', // every four hours
     async () => {
       try {
         await backupDB();
       } catch (e) {
         console.warn('encountered error while trying to backup database', e);
       }
     },
   );
   schedule.scheduleJob(
     '0 3 ? * 0', // every Sunday at 3:00 AM in the keyserver's timezone
     async () => {
       try {
         await updateAndReloadGeoipDB();
       } catch (e) {
         console.warn(
           'encountered error while trying to update GeoIP database',
           e,
         );
       }
     },
   );
   schedule.scheduleJob(
     '0 0 * * *', // every day at midnight in the keyserver's timezone
     async () => {
       try {
         if (process.env.RUN_COMM_TEAM_DEV_SCRIPTS) {
           // This is a job that the Comm internal team uses
           await createDailyUpdatesThread();
         }
       } catch (e) {
         console.warn(
           'encountered error while trying to create daily updates thread',
           e,
         );
       }
     },
   );
-
+  schedule.scheduleJob(
+    '0 5 * * *', // every day at 5:00 AM in the keyserver's timezone
+    async () => {
+      try {
+        await updateIdentityReservedUsernames();
+      } catch (e) {
+        console.warn(
+          'encountered error while trying to update reserved usernames on ' +
+            'identity service',
+          e,
+        );
+      }
+    },
+  );
   schedule.scheduleJob(
     '0 0 * * *', // every day at midnight in the keyserver's timezone
     async () => {
       try {
         await fetchCallUpdateOlmAccount('content', validateAccountPrekey);
         await fetchCallUpdateOlmAccount('notifications', validateAccountPrekey);
       } catch (e) {
         console.warn('encountered error while trying to validate prekeys', e);
       }
     },
   );
 }
diff --git a/keyserver/src/cron/update-identity-reserved-usernames.js b/keyserver/src/cron/update-identity-reserved-usernames.js
new file mode 100644
index 000000000..dfdd15aa4
--- /dev/null
+++ b/keyserver/src/cron/update-identity-reserved-usernames.js
@@ -0,0 +1,28 @@
+// @flow
+
+import { getRustAPI } from 'rust-node-addon';
+
+import type { ReservedUsernameMessage } from 'lib/types/crypto-types.js';
+
+import { fetchAllUsernames } from '../fetchers/user-fetchers.js';
+import { fetchOlmAccount } from '../updaters/olm-account-updater.js';
+
+async function updateIdentityReservedUsernames(): Promise<void> {
+  const [usernames, rustAPI, accountInfo] = await Promise.all([
+    fetchAllUsernames(),
+    getRustAPI(),
+    fetchOlmAccount('content'),
+  ]);
+  const issuedAt = new Date().toISOString();
+  const reservedUsernameMessage: ReservedUsernameMessage = {
+    statement: 'Add the following usernames to reserved list',
+    payload: usernames,
+    issuedAt,
+  };
+  const stringifiedMessage = JSON.stringify(reservedUsernameMessage);
+  const signature = accountInfo.account.sign(stringifiedMessage);
+
+  await rustAPI.addReservedUsernames(stringifiedMessage, signature);
+}
+
+export { updateIdentityReservedUsernames };