Secure VoIP Using a Bare PC

Bare PC applications do not use an operating system or hard disk. We present a lightweight VoIP security scheme for a bare PC softphone that consists of an RSA-based key exchange, AES voice encryption, and SHA-1 data integrity and authentication. The scheme is easily extended to incorporate replay protection and a key derivation function as specified in SRTP for example. Experimental results comparing this security scheme on bare PC and Windows softphones show that the bare PC softphone has packet inter-arrival times (delta) that are closer to the ideal value, and intrinsic jitter values that are smaller and less variable. Moreover, the total time to complete the key exchange, and the time to generate RSA keys of various sizes or a number of RSA keys of a given size are significantly less on the bare PC softphone.