Freeware Applications

CryptoPad

[Version described: 4.09]

The standard NotePad application allows you to write notes of up to 4096 characters. This is about 600 words, or one to two pages of text. While this is fine for a set of directions to a location, a trip itinerary, or other short piece of text, it is far too little for more substantial works.

The Palm OS also allows records to be marked “private,” and there is a global device setting to instruct applications to hide, mask, or show private records. However, marking records “private” does not in fact protect them. Not displaying records marked as “private” is simply a convention in the Palm OS world. Applications can easily read the private records of other applications’ databases. More troubling is the backup copy on the HotSync desktop: “private” records have a particular bit set, but their “private” contents are easily visible in, for example, NotePad.

CryptoPad is a freeware application that addresses both of these concerns. CryptoPad allows each memo to be up to 32,767 characters long—about 5,000 words. CryptoPad also provides strong encryption to make memos inaccessible without a pass phrase.

CryptoPad is designed to be a drop-in replacement for the built-in Memo Pad application. CryptoPad uses the Memo Pad database for entries that have not been encrypted, and so interoperates with other programs that export to and import from memos. Its user interface is almost identical to that of Memo Pad, and its editing “feel” is identical to that of Memo Pad.

CryptoPad lets you encrypt and decrypt single memos or all memos in a category. When editing an encrypted memo, CryptoPad will save the memo encrypted to the same key as before, unless you remove the encryption. CryptoPad also will re-encrypt the memo before permitting a switch to another application and before permitting the device to power off.

CryptoPad has one drawback: memos longer than 4096 characters must be encrypted to protect them during HotSync operations. Otherwise, the Palm Desktop will recognize these records in the Memo Pad database as too long, and truncate them—throw away the excess over 4096 characters. To warn you of this condition, Crypto Pad will display the message “>4k” near the Graffiti shift indicator.

CryptPad provides “strong encryption.” This means the encryption algorithm—Blowfish, in this case—has been extensively studied by cryptanalysts, no attacks quicker than brute force are known or even strongly suspected to exist, and brute force is computationally infeasible. While encryption will likely not protect your secrets from major governments—who could abduct and torture you, or less anti-socially replace your Palm OS device with one that secretly transmitted your secrets to them—it will withstand less determined attacks. However, the strength of encryption depends on the strength, or “entropy,” of the key. Names of partners or pets, birthdates, and so forth are exceptionally poor choices for encryption keys. The best keys are randomly chosen. I recommend Diceware pass phrases, which you generate by rolling dice. See the diceware site for details.

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Copyright © 2002 Brian Hetrick
Page last updated 15 July 2003.