Personal Security Environment on Palm PDA

Digital signature schemes are based on the assumption that the signing key is kept in secret. Ensuring that this assumption holds is one of the most crucial problems for all current digital signature applications. This paper describes the solution developed and prototyped by the authors – using a mobile computing device with a smart card reader for creating digital signatures. We give an overview of several common settings for digital signature applications and problems they have, describing also several frameworks for mobile security applications. A discussion about the choice of devices, design issues, concrete solutions and their security concerns follows. We conclude that although nothing can prevent careless private key handling, careful management is easier and more convenient when using our solu-