A security model of voice eavesdropping protection over SIP-based VoIP with XTR cryptography

The present work is to develop an effective security model of voice eavesdropping protection over SIP-based VoIP. It is based on XTR cryptography approach, and a partial encryption scheme accompanied with a longer cycle loop as an extension from the previous study. XTR is an algorithm for public key cryptography. Our work is to apply XTR cryptographic scheme for key setup and key exchange with XTR Diffie-Hellman (XTR-DH) key agreement protocol, and security protection by encryption and decryption with a shared secret key for the use of XTR cryptography. Furthermore, we extend the previous work of partial encryption scheme known as M:N by varying both M and N in incremental steps. By this way, the cycle loop could be extended even further, as to make it more difficult to hack the hidden key for eavesdropping protection. A system prototype is built based on the aforementioned concept and tested with a number of experimental trials. It is found that the prototype could work well in terms of efficiency and effectiveness for voice eavesdropping protection as proposed.