Recovering From A Locked Device; Passphrases; Performance Considerations Related To Data Encryption - HP iPAQ 4500 Overview

Recovering from a locked device

If the device locks and you enter a correct answer to the pre-selected question, this regains access
to the device and its data. If you forget the PIN/password and the answer to the preselected
question, there is no way to recover from a locked device without losing data. The device will
prompt for a hard or clean reset, and all memory will be set back to the default factory condition
which includes deleting data in the iPAQ File Store. If this option is chosen, the iPAQ File Store
takes more than 10 minutes to initialize. During this initialization process, it is recommended that
you connect your HP iPAQ to AC power to avoid timeouts.
However, if you forget your PIN, but successfully enter your hint question/answer, you are prompted
to enter a new PIN. If you do not answer the hint question/answer successfully, there is a time delay
between the hint question/answer attempts until you enter the correct answer.

Passphrases

When HP ProtectTools is initiated, you are prompted for a passphrase that is different than the PIN
or password used to access the device. The passphrase is created for one reason: if data is stored
on a memory card and encrypted by HP ProtectTools, a passphrase is used to facilitate sharing the
data with other HP iPAQ devices. In other words, HP iPAQ devices that use the same passphrase
can also share the data that is encrypted on memory cards.
One special example occurs when HP ProtectTools is disabled but data is still encrypted on a
memory card. This data can be retrieved from the card if HP ProtectTools is reinitiated on the HP
iPAQ using the same passphrase used previously when the data was encrypted on the card. Thus,
like PINs and passwords, it is important to store the passphrase in a secure location. Passphrases
must be at least eight characters long and must include at least one punctuation mark. For best
results, a mix of at least 30 numbers, letters, and special characters should be used.

Performance considerations related to data encryption

With HP ProtectTools, the HP iPAQ automatically encrypts data stored on the device using one of
four encryption algorithms. These encryption algorithms are listed below in order of the strongest to
the weakest:
• Lite
• AES (advanced encryption standard)
• Blowfish
• 3DES
When you lock and unlock the device, the HP iPAQ encrypts and decrypts the data using whichever
algorithm is chosen. Since the computer must run all data through this algorithm, the
encryption/decryption operation will take time and affect the performance of the device.
If you have a large amount of data on your device and choose to encrypt it all, regardless of
processor performance, it will take time to decrypt the data To improve performance, you may
consider encrypting only the most critical data. Performance can also be improved somewhat by
moving to weaker encryption algorithm. For instance, someone using AES for encryption can see a
small performance improvement by changing to the Blowfish method, which is still strong but not
quite as strong as AES. It is possible to change the encryption settings later, but this also involves a
wait while the data is being converted from one format to the other.
Encrypting your personal data is the best way to protect your personal information. The encryption
process runs in the background, so you are able to perform other tasks on your HP iPAQ during this
time. There are two methods to monitor the decryption process. To find out more about encrypting
and decrypting data, refer to the documentation on the Companio n CD or Getting Started CD that
came with your HP iPAQ.
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