Codebook ($2.99) is Zetetic’s highly rated secure and encrypted notebook application.

It protects your secret notes, ideas, and personal information from unauthorized access by would-be crackers, thieves and snoopy coworkers. Codebook keeps your information secure, yet always at your fingertips.

If you are looking for a notebook application for sensitive info, this is the app for you. Familiar and uncluttered, this digital diary offers a simple interface for finding and editing notes.

Order notes by creation or update time and email notes from inside the application. Codebook also features an auto-save so as not to lose entries when a call comes in.

Codebook is not only an affordable solution to securing your notes and ideas- it also maintains one of the highest customer ratings available in the iTunes App store.

Lots of applications make poor choices when implementing tough encryption algorithms that can leave your data exposed.

Codebook uses OpenSSL and SQLCipher, providing peer-reviewed implementations of 256-bit AES and full-database encryption.

In addition, we protect your password using PBKDF2 to make brute force attacks even more difficult. This is security you can trust.

So whether you’re a secret agent or an insecure poet, Codebook will keep your sensitive materials under lock and passkey.