PDAs and other handheld devices are commonly used for processing private or otherwise secret information. Their increased usage along with their networking capabilities raises security considerations for the protection of the sensitive information they contain and their communications. We present CryptoPalm, an extensible cryptographic library for the PalmOS. The library integrates a large set of cryptographic algorithms and is compatible with the IEEE P1363 standard. Furthermore, the library offers performance comparable with that of independent, application-centric implementations of the cryptographic algorithms. CryptoPalm is beneficial for PalmOS software developers, since it provides established cryptographic algorithms as an infrastructure for meeting their applications' security requirements.