Midori: A Block Cipher for Low Energy (Extended Version)

In the past few years, lightweight cryptography has become a popular research discipline with a number of ciphers and hash functions proposed. The designers\u27 focus has been predominantly to minimize the hardware area, while other goals such as low latency have been addressed rather recently only. However, the optimization goal of low energy for block cipher design has not been explicitly addressed so far. At the same time, it is a crucial measure of goodness for an algorithm. Indeed, a cipher optimized with respect to energy has wide applications, especially in constrained environments running on a tight power/energy budget such as medical implants. This paper presents the block cipher Midori that is optimized with respect to the energy consumed by the circuit per bit in encryption or decryption operation. We deliberate on the design choices that lead to low energy consumption in an electrical circuit, and try to optimize each component of the circuit as well as its entire architecture for energy. An added motivation is to make both encryption and decryption functionalities available by small tweak in the circuit that would not incur significant area or energy overheads. We propose two energy-efficient block ciphers Midori128 and Midori64 with block sizes equal to 128 and 64 bits respectively. These ciphers have the added property that a circuit that provides both the functionalities of encryption and decryption can be designed with very little overhead in terms of area and energy. We compare our results with other ciphers with similar characteristics: it was found that the energy consumptions of Midori64 and Midori128 are by far better when compared ciphers like PRINCE and NOEKEON

T.: Power analysis to ECC using differential power between multiplication and squaring

Abstract. Power analysis is a serious attack to implementation of elliptic curve cryptosystems (ECC) on smart cards. For ECC, many power analysis attacks and countermeasures have been proposed. In this paper, we propose a novel power analysis attack using differential power between modular multiplication and modular squaring. We show how this difference occurs in CMOS circuits by counting the expectation of signal transition frequency, and present a simulation result on our ECC co-processor. The proposed attack is applicable to two efficient power analysis countermeasures based on unified addition formulae and elliptic curves with Montgomery form

Inverse Gating for Low Energy Block Ciphers

In this paper we explore the technique of “inverse gating” which is a significant improvement over the ”round gating” technique introduced in HOST 2016. Round gating worked by generating timing signals to separate glitch propagation from one circuit element to the next. Inverse gating generates the same timing signals required to segregate transient round signals, in a manner that incurs less delay and hence lesser switching activity in the circuits. We also show that energy-wise, inverse gated circuits outperform round gated circuits by a margin of around 30 %. In the second part of the paper, we further explore the efficiency of the energy reduction by tuning some of the design parameters. The most natural candidate for this was the delay of the buffer used for creating the timing signals. We found that the optimal energy consumption for any round and inverse gated unrolled block cipher occurs at a particular range of this delay value. We try to explain the optimality of this particular choice of design parameter with the help of the implementation of the AES-128 block cipher

Granulocyte macrophage colony-stimulating factor is required for aortic dissection/intramural haematoma.

Aortic dissection and intramural haematoma comprise an aortopathy involving separation of the aortic wall. Underlying mechanisms of the condition remain unclear. Here we show that granulocyte macrophage colony-stimulating factor (GM-CSF) is a triggering molecule for this condition. Transcription factor Krüppel-like factor 6 (KLF6)-myeloid-specific conditional deficient mice exhibit this aortic phenotype when subjected to aortic inflammation. Mechanistically, KLF6 downregulates expression and secretion of GM-CSF. Administration of neutralizing antibody against GM-CSF prevents the condition in these mice. Conversely, administration of GM-CSF in combination with aortic inflammation to wild-type mice is sufficient to induce the phenotype, suggesting the general nature of effects. Moreover, patients with this condition show highly increased circulating levels of GM-CSF, which is also locally expressed in the dissected aorta. GM-CSF is therefore a key regulatory molecule causative of this aortopathy, and modulation of this cytokine might be an exploitable treatment strategy for the condition