Reliable Voice-Based Transactions over VoIP Communications

Nowadays, plenty of sensitive transactions are provided through call centers such as bank operations, goods purchase and contracts signing. Beside communication confidentiality, two major issues are raised within this scenario: (1) each peer should be ensured about the identity of the other, (2) each peer should be guaranteed that the other could not cheat about the communication contents. Current telecommunication (TLC) networks offer (built-in) or allow several mechanisms to enhance security and reliability of human conversations, leveraging strong authentication mechanisms and cryptography. However, in most cases these solutions require complex deployments, mainly based on proprietary technologies which are often characterized by high costs and low flexibility. In this paper we present a solution for strong peers authentication and non-repudiability of human conversations through Voice over IP (VoIP) networks. Our solution achieves low costs and high interoperability as it is built on top of open standard technologies. Authentication and key-agreement mechanism are based on X.509 digital certificates and full PKCS#11 compliant cryptographic tokens. As proof of concept, we present and discuss a prototype implementation.