Many people take files with them. Many of these files end up on the memory card since the devices memory is too small. Some of these files are confidential and need some protection.

Although Windows Mobile 6 introduced datacard encryption and wiping, this might not be powerfull enough for some of us. The file encryption of memorycards in Windows Mobile 6 is 128-bit AES encryption, where the key is stored on the device. This key can not be backed-up, but it is destroyed if the device gets hard reset, is involved in a remote wipe or physically damaged. So to some people this might not be acceptable. 

You might want to be able to rescue data or manage encryption keys centrally. Or you own older devices. For these situations there are also tools, that allowing you to set a power-on password and encrypt data on the device and memory-cards, protecting notes, files and complete applications:

• FileBarricader 2007, freeware file encryption based on AES/Rijndael encryption. Please note that the developer is out of business so there is no support for this application.
• SecureWord (Freeware) protects files and passwords using AES/Rijndael encryption
• CCrryyppttoo a freeware file encryption application
• Applian Technologies PocketLock (commercial, $20.00) encrypts files and folders.
• FreeOTFE, a free file encryption application supporting AES
• SecuBox (commercial, $40.00), transparant 256 bit AES file encryption
• Sentry 2020 for Pocket PC (US $50.00), please observe that they do not provide AES encryption

Please note that  more advanced business features, like centrally (remote) management of encryption keys, are only provided by commercial enterprise solutions. These enterprise solutions generally go beyond encryption, but also provide key recovery (which is a big weakness in Windows Mobile), password management and policies. Disadvantage of third-party solutions is that implementation is not fully transparent and additional software has to be installed, implying that the user has to understand the need for encryption. So using a transparent solution, like Windows Mobile 6’s encryption, is preferable when acceptable with respect to key management (which is absent).

Enterprise solutions are:

• Pointsec Mobile, an enterprise ready encryption solution
• DataArmor, enterprise based solution that provides a startup password and file encryption
• McAfee Endpoint encryption for Mobile devices, enterprise solution that provides an integrated password and file encryption application (completely central managed).
• Utimaco Safeguard PDA, an enterprise ready solution that provides password and file encryption application that protects the complete device, also completely centrally managed solution. It is unclear if they still deliver this product since Utimaco has been aquired by Sophos.
• Credant Mobile Enterprise Security suite
• Trust Digital Mobile Edge Device Security, a mobile password and file encryption application that even protects internet and connections with a firewall. Also provides on-device policies.