Rocket.Chat/app/e2e/server/beforeCreateRoom.js

import { callbacks } from '../../callbacks/server';
import { settings } from '../../settings/server';

callbacks.add('beforeCreateRoom', ({ type, extraData }) => {
	if (
		(type === 'd' && settings.get('E2E_Enabled_Default_DirectRooms'))
		|| (type === 'p' && settings.get('E2E_Enabled_Default_PrivateRooms'))
	) {
		extraData.encrypted = true;
	}
});