Apps need certain authorisations to access particular functions and services. An app can usually always access a mobile device's Internet connection, for instance. The device's location or address book, on the other hand, are usually subject to separate approval. If apps are used that require authorisations that are too extensive or not sufficiently restricted, it can affect the confidentiality and integrity of the information on the corresponding end device. Apps can also share other data such as locations, photos, or contact and calendar information with unauthorised third parties. They are also able to change or delete data that is stored locally. Finally, apps can also generate costs, such as through telephone calls, sent SMS messages, or in-app purchases.