Non-Repudiation in Internet Telephony

TL;DR

This paper introduces a method for ensuring non-repudiation in Internet telephony by applying chained electronic signatures to voice data, securing integrity, authenticity, and temporal order, enabling legally binding verbal agreements.

Contribution

It presents a novel approach to non-repudiation in VoIP using chained signatures, extending to multilateral scenarios and enabling legally binding voice communications.

Findings

Developed a concept for non-repudiation in VoIP

Implemented a secure VoIP archive prototype

Achieved high security and potential legal enforceability

Abstract

We present a concept to achieve non-repudiation for natural language conversations over the Internet. The method rests on chained electronic signatures applied to pieces of packet-based, digital, voice communication. It establishes the integrity and authenticity of the bidirectional data stream and its temporal sequence and thus the security context of a conversation. The concept is close to the protocols for Voice over the Internet (VoIP), provides a high level of inherent security, and extends naturally to multilateral non-repudiation, e.g., for conferences. Signatures over conversations can become true declarations of will in analogy to electronically signed, digital documents. This enables binding verbal contracts, in principle between unacquainted speakers, and in particular without witnesses. A reference implementation of a secure VoIP archive is exhibited.