Towards Better Availability and Accountability for IoT Updates by means of a Blockchain

International audienceBuilding the Internet of Things requires deploying a huge number of devices with full or limited connectivity to the Internet. Given that these devices are exposed to attackers and generally not secured-by-design, it is essential to be able to update them, to patch their vulnerabilities and to prevent hackers from enrolling them into botnets. Ideally, the update infrastructure should implement the CIA triad properties, i.e., confidentiality, integrity and availability. In this work, we investigate how the use of a blockchain infrastructure can meet these requirements, with a focus on availability

Decim v2

The original publication is available at www.springerlink.comIn this paper, we present Decimv2, a stream cipher hardware- oriented selected for the phase 3 of the ECRYPT stream cipher project eSTREAM. As required by the initial call for hardware-oriented stream cipher contribution, Decimv2 manages 80-bit secret keys and 64-bit public initialization vectors. The design of Decimv2 combines two filtering mechanisms: a nonlinear Boolean filter over a LFSR, followed by an irregular decimation mechanism called the ABSG. Since designers have been invited to demonstrate flexibility of their design by proposing vari-ants that take 128-bit keys, we also present a 128-bit security version of Decim called Decim-128

Ongoing Research Areas in Symmetric Cryptography

This report is a deliverable for the ECRYPT European network of excellence in cryptology. It gives a brief summary of some of the research trends in symmetric cryptography at the time of writing. The following aspects of symmetric cryptography are investigated in this report: • the status of work with regards to different types of symmetric algorithms, including block ciphers, stream ciphers, hash functions and MAC algorithms (Section 1); • the recently proposed algebraic attacks on symmetric primitives (Section 2); • the design criteria for symmetric ciphers (Section 3); • the provable properties of symmetric primitives (Section 4); • the major industrial needs in the area of symmetric cryptography (Section 5)

Short Signatures in the Random Oracle Model

We study how digital signature schemes can generate signatures as short as possible, in particular in the case where partial message recovery is allowed. We give a concrete proposition named OPSSR that achieves the lower bound for message expansion, and give an exact security proof of the scheme in the ideal cipher model. We extend it to the multi-key setting. We also show that this padding can be used for an asymmetric encryption scheme with minimal message expansion

How to repair ESIGN

The ESIGN signature scheme was provided with an inadequate proof of security. We propose two techniques to repair the scheme, which we name ESIGN-D and ESIGN-R

RSA hybrid encryption schemes

This document compares the two published RSA-based hybrid encryption schemes having linear reduction in their security proof: RSA-KEM with DEM1 and RSA-REACT. While the performance of RSA-REACT is worse than the performance of RSA-KEM+DEM1, a complete proof of its security has already been published. This is indeed an advantage, because we show that the security result for RSA-KEM+DEM1 has a small hole. We provide here a complete proof of the security of RSA-KEM+DEM1. We also propose some changes to RSA-REACT to improve its efficiency without changing its security, and conclude that this new RSA-REACT is a generalisation of RSA-KEM+DEM1, with at most the same security, and with possibly worse performance. Therefore we show that RSA-KEM+DEM1 should be preferred to RSA-REACT

Short Signatures in the Random Oracle Model

We study how digital signature schemes can generate signatures as short as possible, in particular in the case where partial message recovery is allowed. We give a concrete proposition named OPSSR that achieves the lower bound for message expansion, and give an exact security proof of the scheme in the ideal cipher model. We extend it to the multi-key setting. We also show that this padding can be used for an asymmetric encryption scheme with minimal message expansion