Handheld wireless communications devices include a data input device, which is configured to receive first input data provided by a user, a main processor and a security processor. The security processor includes an input interface and input processing block configured to extract second data from a first portion of the first input data using, for example, a data mapping operation. The security processor also includes an encryption circuit, which is configured generate secure data from the extracted second data by encrypting the extracted second data using an encryption key, and a data/control interface, which is configured to transfer the secure data to the main processor.