1 Approaching decentralized non-repudiation H. Kamdem Fezeu 1, *, T. Djotio 2 and R. Oulad Haj Thami 3 1 University of Yaounde I, harry.kamdem@polytechnique.cm 2 University of Yaounde I, tdjotio@gmail.com 3 Mohammed V University, rachid.ouladhajthami@gmail.com Abstract Securing data exchanges is a major preoccupation, and several techniques have been developed to reach that aim. The predominant model for such exchange is that which relies on trusted third-parties. Meanwhile, emerging technologies such as IoT are set to broadcast growing amounts of sensitive data, thereby making centralized architectures problematic for privacy and performance reasons and making decentralized networks ever more relevant. However, these third-parties play an important role in securing brokered communications and are essential in providing Authentication and Non-Repudiation according to current models, and cannot be used in peer-to-peer networks. Hence there is need for a simple model applicable in fully decentralized networks to provide Non-Repudiation. This document proposes such a model, presents an implementation and discusses its application, particularly in implementing irrefutable trustless transaction mechanisms – similar to blockchain – with limited resources. Keywords: Information Security, Internet of Things, Mesh Networks, Blockchain Received on 15 December 2017, accepted on 5 January, 2018, published on 12 January 2018 Copyright © 2018 Author et al., licensed to EAI. This is an open access article distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/3.0/), which permits unlimited use, distribution and reproduction in any medium so long as the original work is properly cited. doi: 10.4108/eai.12-1-2018.153559 1. Introduction The basic requirements of Information Security, are generally referred to as the “CIA triad” [1], comprising Confidentiality (ensuring that information is not disclosed to non-authorized third-parties), Integrity (ensuring that information is not altered during transit) and Availability (ensuring that information reaches the correct recipients). Several cryptographic techniques have been adapted to autonomous distributed networks and as such, the basic tenets of the “CIA triad” can successfully be fulfilled in a Mesh Network. Nonetheless, there exists a number of issues which re-quire different forms of security such as Authentication and Non-repudiation which are not generally addressed. On the internet, the implementation of such characteristics generally involves the introduction of a Trusted Third-Party allowing for brokered communication, typically in a client-server model. Such an entity serves as middle-man or notary, and may leverage other * Corresponding author. Email:kamdemharry@gmail.com technologies to further secure communications (SSL, PGP, etc.). However, in a peer-to-peer net-work, such a solution would be impractical as any node may leave the network at any moment and no node is to be inherently trusted. This paper presents a cryptographic approach to securing communications, which allows for Non- repudiation and Authentication in addition to Confidentiality, Integrity and Availability, and which can readily be implemented in decentralized networks, as well as overlaid on existing infrastructure. It starts out with a brief overview of the existing literature, and then presents the proposed communication model, before discussing the principle and results of an experimental implementation, and goes on to discuss the pertinence of the said model as an alternative to blockchain in scenarios with little computing resources before ending with concluding remarks. EAI Endorsed Transactions on Future Internet Research Article EAI Endorsed Transactions on Future Internet 12 2017 - 01 2018 | Volume 4 | Issue 13 | e2