Power Analysis Attacks on Keccak

Side Channel Attacks (SCA) exploit weaknesses in implementations of cryptographic functions resulting from unintended inputs and outputs such as operation timing, electromagnetic radiation, thermal/acoustic emanations, and power consumption to break cryptographic systems with no known weaknesses in the algorithm’s mathematical structure. Power Analysis Attack (PAA) is a type of SCA that exploits the relationship between the power consumption and secret key (secret part of input to some cryptographic process) information during the cryptographic device normal operation. PAA can be further divided into three categories: Simple Power Analysis (SPA), Differential Power Analysis (DPA) and Correlation Power Analysis (CPA). PAA was first introduced in 1998 and mostly focused on symmetric-key block cipher Data Encryption Standard (DES). Most recently this technique has been applied to cryptographic hash functions. Keccak is built on sponge construction, and it provides a new Message Authentication Code (MAC) function called MAC-Keccak. The focus of this thesis is to apply the power analysis attacks that use CPA technique to extract the key from the MAC-Keccak. So far there are attacks of physical hardware implementations of MAC-Keccak using FPGA development board, but there has been no side channel vulnerability assessment of the hardware implementations using simulated power consumption waveforms. Compared to physical power extraction, circuit simulation significantly reduces the complexity of mounting a power attack, provides quicker feedback during the implementation/study of a cryptographic device, and that ultimately reduces the cost of testing and experimentation. An attack framework was developed and applied to the Keccak high speed core hardware design from the SHA-3 competition, using gate-level circuit simulation. The framework is written in a modular fashion to be flexible to attack both simulated and physical power traces of AES, MAC-Keccak, and future crypto systems. The Keccak hardware design is synthesized with the Synopsys 130-nm CMOS standard cell library. Simulated instantaneous power consumption waveforms are generated with Synopsys PrimeTime PX. 1-bit, 2-bit, 4-bit, 8-bit, and 16-bit CPA selection function key guess size attacks are performed on the waveforms to compare/analyze the optimization and computation effort/performance of successful key extraction on MAC-Keccak using 40 byte key size that fits the whole bottom plane of the 3D Keccak state. The research shows the larger the selection function key guess size used, the better the signal-noise-ratio (SNR), therefore requiring fewer numbers of traces needed to be applied to retrieve the key but suffer from higher computation effort time. Compared to larger selection function key guess size, smaller key guess size has lower SNR that requires higher number of applied traces for successful key extraction and utilizes less computational effort time. The research also explores and analyzes the attempted method of attacking the second plane of the 3D Keccak state where the key expands beyond 40 bytes using the successful approach against the bottom plane

Genetic interaction between two VNTRs in the MAOA gene is associated with the nicotine dependence

Nicotine dependence is an addiction to tobacco products and a global public health concern that in part would be influenced by our genetics. Smokers are reported to have reduced MAOA activity, but the results from genetic associations with this gene have been inconclusive. Two functionally relevant variable number tandem repeat (VNTR) domains, termed uVNTR and dVNTR, in the MAOA gene are well characterized transcriptional regulatory elements. In the present study, we analyzed uVNTR and dVNTR polymorphisms in the MAOA gene in the Vietnamese male population of smokers and non-smokers in order to assess the association of MAOA with the nicotine dependence measured by the Fagerström Test for Nicotine Dependence (FTND). Individual analysis of VNTRs separately identified uVNTR to be associated with the F6 question of the FTND indicating the stronger addiction to nicotine. No associations were found between the dVNTR and smoking behavior. The combination of dVNTR and uVNTR, that predicts low expression of MAOA (10–3 haplotypes), was significantly associated with the higher nicotine dependence (FTND score), longer smoking duration, and more persistent smoking behavior (fewer quit attempts). In conclusion, our study confirms that low MAOA expression is genetically predictive to the higher nicotine dependence

Formation of Low Volatility Organic Compounds and Secondary Organic Aerosol from Isoprene Hydroxyhydroperoxide Low-NO Oxidation

Gas-phase low volatility organic compounds (LVOC), produced from oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC directly correspond to appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA below 1 μg m^(–3)). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The SOA formation in this study is separate from previously described isoprene epoxydiol (IEPOX) uptake. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxidation in the chamber study implies a wall-loss corrected non-IEPOX SOA mass yield of ∼4%. By contrast to monoterpene oxidation, in which extremely low volatility VOC (ELVOC) constitute the organic aerosol, in the isoprene system LVOC with saturation concentrations from 10^(–2) to 10 μg m^(–3) are the main constituents. These LVOC may be important for the growth of nanoparticles in environments with low OA concentrations. LVOC observed in the chamber were also observed in the atmosphere during SOAS-2013 in the Southeastern United States, with the expected diurnal cycle. This previously uncharacterized aerosol formation pathway could account for ∼5.0 Tg yr^(–1) of SOA production, or 3.3% of global SOA

Mechanism of the hydroxyl radical oxidation of methacryloyl peroxynitrate (MPAN) and its pathway toward secondary organic aerosol formation in the atmosphere

Methacryloyl peroxynitrate (MPAN), the acyl peroxynitrate of methacrolein, has been suggested to be an important secondary organic aerosol (SOA) precursor from isoprene oxidation. Yet, the mechanism by which MPAN produces SOA through reaction with the hydroxyl radical (OH) is unclear. We systematically evaluate three proposed mechanisms in controlled chamber experiments and provide the first experimental support for the theoretically-predicted lactone formation pathway from the MPAN + OH reaction, producing hydroxymethyl-methyl-α-lactone (HMML). The decomposition of the MPAN–OH adduct yields HMML + NO_3 ( 75%) and hydroxyacetone + CO + NO_3 ( 25%), out-competing its reaction with atmospheric oxygen. The production of other proposed SOA precursors, e.g., methacrylic acid epoxide (MAE), from MPAN and methacrolein are negligible (<2%). Furthermore, we show that the beta-alkenyl moiety of MPAN is critical for lactone formation. Alkyl radicals formed cold via H-abstraction by OH do not decompose to HMML, even if they are structurally identical to the MPAN–OH adduct. The SOA formation from HMML, from polyaddition of the lactone to organic compounds at the particle interface or in the condensed phase, is close to unity under dry conditions. However, the SOA yield is sensitive to particle liquid water and solvated ions. In hydrated inorganic particles, HMML reacts primarily with H¬_2O to produce the monomeric 2-methylglyceric acid (2MGA) or with aqueous sulfate and nitrate to produce the associated organosulfate and organonitrate, respectively. 2MGA, a tracer for isoprene SOA, is semivolatile and its accommodation in aerosol water decreases with decreasing pH. Conditions that enhance the production of neutral 2MGA suppress SOA mass from the HMML channel. Considering the liquid water content and pH ranges of ambient particles, 2MGA will exist largely as a gaseous compound in some parts of the atmosphere

Isoprene NO_3 Oxidation Products from the RO_2 + HO_2 Pathway

We describe the products of the reaction of the hydroperoxy radical (HO_2) with the alkylperoxy radical formed following addition of the nitrate radical (NO_3) and O_2 to isoprene. NO_3 adds preferentially to the C_1 position of isoprene (>6 times more favorably than addition to C_4), followed by the addition of O_2 to produce a suite of nitrooxy alkylperoxy radicals (RO_2). At an RO_2 lifetime of ∼30 s, δ-nitrooxy and β-nitrooxy alkylperoxy radicals are present in similar amounts. Gas-phase product yields from the RO_2 + HO_2 pathway are identified as 0.75–0.78 isoprene nitrooxy hydroperoxide (INP), 0.22 methyl vinyl ketone (MVK) + formaldehyde (CH_2O) + hydroxyl radical (OH) + nitrogen dioxide (NO_2), and 0–0.03 methacrolein (MACR) + CH_2O + OH + NO_2. We further examined the photochemistry of INP and identified propanone nitrate (PROPNN) and isoprene nitrooxy hydroxyepoxide (INHE) as the main products. INHE undergoes similar heterogeneous chemistry as isoprene dihydroxy epoxide (IEPOX), likely contributing to atmospheric secondary organic aerosol formation

Vectors and malaria transmission in deforested, rural communities in north-central Vietnam

Background: Malaria is still prevalent in rural communities of central Vietnam even though, due to deforestation, the primary vector Anopheles dirus is uncommon. In these situations little is known about the secondary vectors which are responsible for maintaining transmission. Basic information on the identification of the species in these rural communities is required so that transmission parameters, such as ecology, behaviour and vectorial status can be assigned to the appropriate species