diff --git a/lib/AssetsModule.js b/lib/AssetsModule.js
index 3b9db68..fb5448d 100644
--- a/lib/AssetsModule.js
+++ b/lib/AssetsModule.js
@@ -22,10 +22,14 @@ class Assetsmodule extends AbstractApiModule {
     this.assetTypes = { [LocalAsset.name]: LocalAsset }
 
     await this.ensureLibPermissions()
-    const [authored, mongodb, tags] = await this.app.waitForModule('authored', 'mongodb', 'tags')
+    const [authored, mongodb, tags, users] = await this.app.waitForModule('authored', 'mongodb', 'tags', 'users')
     await mongodb.setIndex(this.collectionName, 'hash')
     await authored.registerModule(this, { accessCheck: false })
     await tags.registerModule(this)
+    // opt into the generic _access model: public access (base) plus per-user sharing.
+    // Group sharing is wired from the usergroups module. See adapt-authoring-api#98.
+    await this.enableAccessControl()
+    await users.registerUserModule(this)
 
     this.router.addMiddleware(this.fileUploadMiddleware)
     this.requestHook.tap(this.onRequest.bind(this))