Smartphones are becoming a repository for a vast range of business and personal documents. Loosing you address book with your phone was bad enough, now all variety of confidential information could be lost with it. Protecting the data on your smartphone with encryption is one line of defense against thieves getting away with more than a nice phone.

Here is where PIN Guard for UIQ comes in, tested here on a Sony Ericsson P910i. The goal of PIN Guard is simple; to secure documents and images on your smartphone. It does this by encrypting files, on both the phone and memory card, and protecting them with a password.

When PIN Guard is first loaded it requests a password, which is used subsequently to encrypt and decrypt files.

Once the password is entered the application's main screen lists the types of files that can be encrypted: documents, spreadsheets, presentations, Adobe Acrobat file and images. Separate lists for the phone memory and memory card are provided.

Encrypting files is simply a case of selecting the file type and location that you wish to encrypt, then pressing the "Apply" button. A progress bar tracks the entire encryption or decryption process. Each selected file type and location is marked in green when all the files are encrypted.

Encrypted files have the extension .enc added to them. This means they cease to be visible in the applications that would normally open them.

Before you can work with the files you now need to decrypt them through PIN Guard. The process is essentially the same as encryption. The locations and file types to be decrypted are deselected and "Apply" pressed again.

If new files are loaded on the phone PIN Guard shows their presence in a location by displaying an incomplete green bar.

To protect these new files all that needs to be done is to press "Apply" again.

We tested the compression and decompression with 10 files, totaling about 2 MB, on both the phone memory and card. One or two files of each type were present. We found the times for encryption and decryption to be about the same. For our test data processing the phone memory took about 45 seconds while the memory card took just over 2 minutes. This prompted us to do a larger test, we loaded approximately 10Mb of document file onto the memory card and selected encrypt, encryption took over 12 minutes.

PIN Guard effectively hides files and the data within them. A few, admittedly rudimentary, attempt at accessing the encrypted data proved fruitless. However, while the protection looks good there are two real issues with PIN Guard.

First, the time it takes to encrypt files may be too slow for many. A reasonable capacity data card with a substantial number of documents stored on it could take a considerable time to encrypt, maybe up to an hour for 64MB. While encryption can probably be left to run unattended, decryption to access a file would be less than convenient. To make it practical you would need to shuffle files around so, for example, you could use the phone memory to decrypt individual files.

Secondly, PIN Guard's batch style operation may mean that it is less than effective in its intended purpose. It requires some discipline in encrypting files when work on them is finished and then remembering to log out of PIN Guard (it does not even seem to have an automatic lockout based on inactivity). It would seem all too likely that the haste that might mean you skip encrypting files is the same haste that results in loss of the phone.

PIN Guard is a great idea, but hampered by the speed at which files are encrypted and decrypted. A couple of minor improvements, such as the ability to select individual files for decryption and either an "Apply and Logout" or automatic timed logout, would make it significantly more usable. However, knowing your data is protected could easily out weight these issues.

PIN Guard can be obtained directly from SMobile Systems' web site or from Handango. It costs $19.99. SMobile Systems also makes virus protection software for Symbian OS devices.