Smart Password Store saves a database of user and passwords, under a unique password key in the form of an encrypted image. The only way to break the password key is by brute force. As the data is being saved as an encrypted image, brute force attacks would have to be done using an OCR (Optical Character Recognition) tool to discover if the image was decrypted correctly.
With todays computers this would take a very long time. Smart Password Store also allows you to create a stub (a small program that will show you your usernames and passwords if you have entered the correct password key). This allows you to carry the sensitive information with you, without having to install Smart Password Store on another computer.