Options for encrypting data on a mobile device will vary according to the operating system used and the operating system version. In general, it can be said that the quality of encryption tends to increase with more recent versions.

Using passwords to block unauthorised access

Before starting to look at options for encrypting your mobile devices, you should first of all set up a screen lock for your smartphone, tablet or other mobile device. Screen locks can usually only be broken by security experts. However, a lock screen provides no protection at all for any removable or external memory cards. You should also avoid using simple combinations of numbers like repeated single digits ("0000") or sequences ("1234").

You should also remember to protect your SIM card with a password or PIN. If the SIM card is then removed from your smartphone or tablet, access to the SIM card will still be blocked without the right password. The data stored on the card will be inaccessible and, if you lose your smartphone or tablet with the card inside, then it will not be possible to make calls or use other paid services by impersonating the owner of the device.

Activating integrated encryption on a mobile device

Many newer models of phones and tablets now offer a device encryption option. This encryption technique is built into the phone or tablet itself and encrypts the entire device, including all of the data that is stored on it. Once activated, user data is protected so well that even the use of extensive resources, including a corresponding hardware lab and specialised expertise, will be unable to crack the code.

Most types of device encryption will require some form of lock screen or display password. The encryption offered by a smartphone will depend both on the manufacturer and the software version. This is also true for configuration or activation options, which can typically be found by consulting the device help or manual. If you are not sure whether your device offers a device encryption option, then you should check the usual online sources for information about encryption options or contact your device maker directly.

Encryption apps

If you only want to encrypt individual items of data such as personal documents, photos or videos, then you will need to install a corresponding app on your mobile device. These kinds of apps can be found on the official app stores. You may also need to check whether a particular app is compatible with your mobile device (the app store may check this for you automatically).

Using additional encryption on individual files can be advisable in several circumstances. If data is stored unencrypted, for example (accessible by any app) and a piece of malware uploads or sends this data somewhere else, then the data can be read by any recipient. If these individual files had been encrypted, however, then they would have been protected in this scenario. In addition, any data that you store on external SD cards or in the cloud is also not protected (encrypted) as part of device encryption.

Making mobile encryption more effective

• Follow good practice rules for mobile patch management
• Always install security updates as quickly as possible.
• Deactivate any option for connecting automatically to public Wi-Fi networks.
• Ensure that you use "safe browsing" settings. On some device models, such as Android devices, these settings are already activated for the pre-installed browser apps. When the settings are active, content accessed by the browser is checked for malware before being accessed and displayed on the smartphone screen. You should therefore always make sure this setting is active.
• Activate wireless interfaces such as Wi-Fi, BlueTooth, GPS and mobile data (mobile internet) only when you really need to use them. This will also improve battery lifetime and save on mobile network fees.
• Rooting and jailbreaking are useful techniques for lab work or special kinds of development work but such devices should never be used on a day-to-day basis. Altering the firmware on a device will typically void the manufacturer's guarantee while also making the effects of malware potentially more damaging. Rooting attempts always run the risk of making the device unusable (bricking).
• One last tip for IT-savvy users: if you have switched on developer mode for test purposes, then you should deactivate it after completing your tests, since developer mode leaves your smartphone in a very vulnerable state.