Sensor-Based Seeds for a Chaotic Stream Cipher

In this paper we have used a surface micromachined capacitive accelerometer in order to generate seeds that are suitable for secure communications between wireless smart sensors for IoT networks. These seeds have then been used in a chaotic stream cipher based on a Modified Logistic Map and a Linear Feedback Shift Register. The sequences generated by the chaotic stream cipher have been subjected to the randomness NIST tests. All the tests have been passed, proving that the proposed approach could be used for secure communications

Self-synchronized Encryption for Physical Layer in 10Gbps Optical Links

In this work a new self-synchronized encryption method for 10 Gigabit optical links is proposed and developed. Necessary modifications to introduce this kind of encryption in physical layers based on 64b/66b encoding, such as 10GBase-R, have been considered. The proposed scheme encrypts directly the 64b/66b blocks by using a symmetric stream cipher based on an FPE (Format Preserving Encryption) block cipher operating in PSCFB (Pipelined Statistical Cipher Feedback) mode. One of the main novelties in this paper is the security analysis done for this mode. For the first time, an expression for the IND-CPA (Indistinguishability under Chosen-Plaintext Attack) advantage of any adversary over this scheme has been derived. Moreover, it has been concluded that this mode can be considered secure in the same way of traditional modes are. In addition, the overall system has been simulated and implemented in an FPGA (Field Programmable Gate Array). An encrypted optical link has been tested with Ethernet data frames, concluding that it is possible to cipher traffic at this level, getting maximum throughput and hiding traffic pattern from passive eavesdroppers

A new simple technique for improving the random properties of chaos-based cryptosystems

A new technique for improving the security of chaos-based stream ciphers has been proposed and tested experimentally. This technique manages to improve the randomness properties of the generated keystream by preventing the system to fall into short period cycles due to digitation. In order to test this technique, a stream cipher based on a Skew Tent Map algorithm has been implemented on a Virtex 7 FPGA. The randomness of the keystream generated by this system has been compared to the randomness of the keystream generated by the same system with the proposed randomness-enhancement technique. By subjecting both keystreams to the National Institute of Standards and Technology (NIST) tests, we have proved that our method can considerably improve the randomness of the generated keystreams. In order to incorporate our randomness-enhancement technique, only 41 extra slices have been needed, proving that, apart from effective, this method is also efficient in terms of area and hardware resources

Physical Layer Encryption for Industrial Ethernet in Gigabit Optical Links

Industrial Ethernet is a technology widely spread in factory floors and critical infrastructures where a high amount of data need to be collected and transported. Fiber optic networks at gigabit rates fit well with that type of environment, where speed, system performance, and reliability are critical. In this paper, a new encryption method for high-speed optical communications suitable for such kinds of networks is proposed. This new encryption method consists of a symmetric streaming encryption of the 8b/10b data flow at physical coding sublayer level. It is carried out thanks to a format preserving encryption block cipher working in CTR (counter) mode. The overall system has been simulated and implemented in a field programmable gate array. Thanks to experimental results, it can be concluded that it is possible to cipher traffic at this physical level in a secure way. In addition, no overhead is introduced during encryption, getting minimum latency and maximum throughput

Introduction to Physically Unclonable Fuctions: Properties and Applications

During the last years, Physically Unclonable Functions (PUFs) have become a very important research area in the field of hardware security due to their capability of generating volatile secret keys as well as providing a low-cost authentication. In this paper, an introduction to Physically Unclonable Functions is given, including their definition, properties and applications. Finally, as an example of how to design a PUF, the general structure of a ring oscillator PUF is presented

A New Approach to Analysis the Security of Compensated Measuring PUFs

In this paper we perform an entropy analysis and probability distribution analysis over simulated PUFs operating under a compensated measuring digitization scheme. The behavior of the PUFs have been simulated by generating a set of pseudorandom numbers uniformly distributed, which simulate the measured parameters, using the definition of the so called "topology of the PUF", i.e. the way in which different parameter measurements are compared to obtain a digital binary output. At this respect, we prove the existence of a shortcoming in the most commonly used PUF topologies. as well as provide some guidelines to overcome it

Self-Synchronized Encryption for Physical Layer in Gigabit Ethernet Optical Links

In this work a new self-synchronized symmetric encryption solution for high speed communication systems necessary to preserve the format of the plaintext is proposed, developed and tested. This new encryption mechanism is based on the block cipher operation mode called PSCFB (Pipelined Statistical Cipher Feedback) and the modulo operation. The confidentiality of this mode is analyzed in terms of its IND-CPA (Indistinguishability under Chosen-Plaintext Attack) advantage, concluding that it can be considered secure in the same way as traditional modes are. The encryption system has been integrated in the physical layer of a 1000Base-X Gigabit Ethernet Interface, where the 8b/10b symbol flow is encrypted at line rate. Moreover, an implementation of the proposed system has been carried out in an FPGA (Field Programmable Gate Array) device. Finally, an encrypted optical link has been tested with real Ethernet frames, getting maximum throughput and protecting the data traffic from passive eavesdroppers

Chaotic Encryption for 10-Gb Ethernet Optical Links

In this paper, a new physical layer encryption method for optical 10-Gb Ethernet links is proposed. Necessary modifications to introduce encryption in Ethernet 10GBase-R standard have been considered. This security enhancement has consisted of a symmetric streaming encryption of the 64b/66b data flow at physical coding sublayer level thanks to two keystream generators based on a chaotic algorithm. The overall system has been implemented and tested in a field programmable gate array. Ethernet traffic has been encrypted, transmitted, and decrypted over a multimode optical link. Experimental results are analyzed concluding that it is possible to cipher traffic at this level and hide the complete Ethernet traffic pattern from any passive eavesdropper. In addition, no overhead is introduced during encryption, getting no losses in the total throughput

Proposal and Analysis of a Novel Class of PUFs Based on Galois Ring Oscillators

In this article, the possibility of using Galois ring oscillators to construct physically unclonable functions (PUFs) has been studied. The idea is to use novel PUF architectures, similar as the ring oscillator PUFs that, instead of comparing frequencies, compare the statistical bias of pairs of oscillators implemented in different locations. To study the viability of these systems, three different Galois oscillators have been implemented in several locations in several FPGAs and we have studied the main properties of their bias: repeatability, variability with the location, variability with the FPGA and spatial autocorrelation. Based on this study, we have determined that the bias of these oscillators meet the requirements that are needed to be used to construct a PUF. Finally, a PUF based on comparing the bias of neighboring 7-LUT Galois ring oscillators have been implemented and analyzed. The experimental results show that this PUF generates uniform responses that are highly reproducible and unique, making this PUF suitable for being used in identification applications

Chaos-Based Bitwise Dynamical Pseudorandom Number Generator on FPGA

In this paper, a new pseudorandom number generator (PRNG) based on the logistic map has been proposed. To prevent the system to fall into short period orbits as well as increasing the randomness of the generated sequences, the proposed algorithm dynamically changes the parameters of the chaotic system. This PRNG has been implemented in a Virtex 7 field-programmable gate array (FPGA) with a 32-bit fixed point precision, using a total of 510 lookup tables (LUTs) and 120 registers. The sequences generated by the proposed algorithm have been subjected to the National Institute of Standards and Technology (NIST) randomness tests, passing all of them. By comparing the randomness with the sequences generated by a raw 32-bit logistic map, it is shown that, by using only an additional 16% of LUTs, the proposed PRNG obtains a much better performance in terms of randomness, increasing the NIST passing rate from 0.252 to 0.989. Finally, the proposed bitwise dynamical PRNG is compared with other chaos-based realizations previously proposed, showing great improvement in terms of resources and randomness