A portable security device for providing secure communications over a
plurality of networks is presented. In one embodiment, the device
comprises, at least one communication port for transfer of audio data, at
least one communication port for transfer of digital data, a keypad, an
encoding/decoding device, a conversion device operable to covert between
audio and digital data and a processor, in communication with a memory,
the keypad, the said encoding/decoding device, operable to execute code
for selecting a configuration of a transmission and a reception port from
among said communication ports dependent upon the presence of a network
communication device and an input/output device in communication with
said selected ports, providing data received from said selected reception
port to said encryption/decryption device for encrypting; and providing
said encrypted data to said selected transmission port. In one aspect of
the invention, encrypted voice data can be transferred over a wireless
network using cellular phones, over a wired and wireless network using
land-based telephones, cellular phones or satellite phones. In another
aspect, encrypted computer data may be transferred over wired or wireless
networks.