Current NIST Research Articles

More efficient tightly-secure lattice-based IBE with equality test

Identity-based encryption with equality test (IBEET) combines public key encryption with equality test (PKEET) and identity-based encryption (IBE). In an IBEET scheme, a user with trapdoors is allowed to verify whether different ciphertexts encrypted under different identities correspond to equal plaintexts through the equality test algorithm. Recently, several IBEET schemes were constructed over lattices to resist the potential quantum threats, perhaps since the latticed-based candidates are the most favored ones in the current NIST PQC standardization. However, almost all of the schemes are developed from Lee et al.’s generic construction and hence double both public parameters and ciphertext sizes. In this paper, we propose a more efficient and tightly-secure IBEET scheme which not only achieves a tight reduction with the semi-adaptive security, but also reduces both public parameters and ciphertext sizes.

Порівняльний аналіз алгоритмів шифрування NTRUEncrypt та NTRUCipher

The asymmetric encryption scheme NTRUEncrypt proposed in 1996 and is one of the fastest post-quantum encryption schemes. It is included in the ANSI X9.98-2010 standard and is the prototype of cryptosystems’ wide class with the same name, which security is based on the difficulty of finding short vectors in some lattices. The cryptographic properties of NTRUEncrypt encryption scheme are sufficiently explored and its latest modifications are presented at the current NIST competition to standardize post-quantum asymmetric encryption, key encapsulation and digital signature.One of the most important problem in the field of cryptology is the design of symmetric encryption schemes, whose security, similarly to the asymmetric one, is based on the complexity of solving only one particular problem (for example, for RSA this is the problem of factorization of numbers). Due to this, in 2017 the symmetric encryption scheme NTRUCipher based on NTRUEncrypt was proposed. For it, a preliminary security analysis was performed and a parameter selection algorithm was proposed. At the same time, there are essential errors in the proof of CPA-se­curity of the encryption algorithm NTRUCipher. Moreover, the problem of comparative analysis of NTRUCipher and NTRUEncrypt encryption schemes is not solved for security and practicality.The purpose of this article is to conduct a comparative analysis of the abovementioned encryption schemes and to prove correctly the conditions that ensure the CPA-security of the NTRUCipher encryption scheme. A certain result is analytical bounds of decryption failure probability in NTRUCipher encryption scheme. This result is important for the proper parameters’ choice of the encryption scheme in its practical implementation. It is shown that the decryption failure probability in the NTRUCipher varies from to while the value of this probability for the NTRUEncrypt encryption scheme varies from to . In addition, the obtained bounds are not based on any heuristic assumptions.

Fully Automated Differential Fault Analysis on Software Implementations of Block Ciphers

Differential Fault Analysis (DFA) is considered as the most popular fault analysis method. While there are techniques that provide a fault analysis automation on the cipher level to some degree, it can be shown that when it comes to software implementations, there are new vulnerabilities, which cannot be found by observing the cipher design specification.This work bridges the gap by providing a fully automated way to carry out DFA on assembly implementations of symmetric block ciphers. We use a customized data flow graph to represent the program and develop a novel fault analysis methodology to capture the program behavior under faults. We establish an effective description of DFA as constraints that are passed to an SMT solver. We create a tool that takes assembly code as input, analyzes the dependencies among instructions, automatically attacks vulnerable instructions using SMT solver and outputs the attack details that recover the last round key (and possibly the earlier keys). We support our design with evaluations on lightweight ciphers SIMON, SPECK, and PRIDE, and a current NIST standard, AES. By automated assembly analysis, we were able to find new efficient DFA attacks on SPECK and PRIDE, exploiting implementation specific vulnerabilities, and previously published DFA on SIMON and AES. Moreover, we present a novel DFA on multiplication operation that has never been shown for symmetric block ciphers before. Our experimental evaluation also shows reasonable execution times that are scalable to current cipher designs and can easily outclass the manual analysis. Moreover, we present a method to check the countermeasure-protected implementations in a way that helps implementers to decide how many rounds should be protected. We note that this is the first work that automatically carries out DFA on cipher implementations without any plaintext or ciphertext information and therefore, can be generally applied to any input data to the cipher.

PTU-138 Feasibility Study of Volatile Organic Compounds in Constipation in Parkinson’s Disease

Introduction Patients with Parkinson’s disease (PD) have constipation. Constipation often precedes the classical motor signs. Enteric neuropathy may play a role of the aetiology of PD. Exposure to fungi is a risk factor for PD: in vitro models have shown specific fungi-produced volatile organic compounds (VOC), 1 octen-3-ol and 2 octanone, may cause loss of dopaminergic neurones in fruit flies. We propose the hypothesis that intestinal fungal metabolites may a risk factor for PD. This study assessed the feasibility of performing faecal VOCs analysis in people with PD and controls. Methods 8 patients with diagnosed PD were invited from an exercise class (Dancing for Parkinson’s). Their partners/carers were also invited as aged-matched controls. Samples from lab volunteers (14) were also analysed. Patients or controls that had taken any antibiotics or antifungals in the 4 weeks prior to sampling were excluded. VOCs from 2 aliquots per donor were extracted using Solid Phase Micro Extraction (SPME), separated by gas chromatography–mass and analysed by gas spectrometry (GC-MS). VOCs were identified using AMDIS and comparison with the current NIST library of mass spectra. Reported were prepared using Metab, and statistical analysis undertaken using Metaboanalyst software. Results All 8 PD patients provided samples, despite their constipation. 5 of 6 aged-matched controls provided samples. The average result from the paired technical replicates was used for statistical analysis. There were significantly fewer VOC in samples from PD patients (63), than from controls (74, p Conclusion The study of VOCs in people with constipation is feasible. Those with constipation have fewer VOCs that controls as a whole. There were clear differences in the VOCs from patients with Parkinson’s disease in the control group. One of the VOCs that was increased, 2 octanone, in Parkinson’s disease is a fungal metabolite that causes damage to dopaminergic neurones in an insect model. More work is necessary to explore the association between PD: a full study will need to include more patients and controls with constipation. Disclosure of Interest None Declared

Thermodynamic Radiation Thermometry for the Next SI

The construction, the calibration, and the use of the NIST Thermodynamic Radiation Thermometer (TRT) to measure the temperature of the gold freezing temperature blackbody and a variable-temperature blackbody from 800 to 2,700°C are described. These temperature determinations are detector-based and derived from the electrical substitution radiometer and length units. The TRT is constructed using a cooled, near-infrared enhanced silicon detector with a room-temperature-stabilized five-position filter wheel. The characteristics of the TRT, such as the size-of-source effect and preamplifier linearity, are determined. The measured temperatures are compared with those obtained using the NIST Absolute Pyrometer 1 (AP1) and the current NIST standard radiation thermometer, the Photoelectric Pyrometer (PEP). After the performance assessments, the TRT will become the standard radiation thermometer for disseminating radiance temperature scales in the United States.

Assessing thermochemical data

This paper describes, with examples, a critical assessment of thermochemical data for some small molecules and free radicals. The available heats of formation, Δ f H° (all 298 K values). for simple alkyl hydroperoxides and di-alkyl peroxides were compared and new data are provided. The Δ f H° values, all ±5 kJ/mol, are: CH 3OOH, −135; CH 3CH 2OOH, −168; n-C 3H 7OOH, −189; s-C 3H 7OOH, −205; t-C 4H 9OOH, −240; CH 3OOCH 3, −132; CH 3CH 2OOCH 3, −165; C 2H 5OOC 2H 5, −198; n-C 3H 7OO n-C 3H 7, −240; s-C 3H 7OO s-C 3H 7, −272; t-C 4H 9OO t-C 4H 9, −342. These are consistent with established O–O bond dissociation energies and with additivity considerations. Δ f H° values for the corresponding alkoxy radicals are also addressed. A similar survey was applied to the homologous n-alkyl aldehydes, C2 to C8, for which recommended Δ f H° values, all ±1.5 kJ/mol, are: −166.5, −189, −207.5, −227, −248, −268 and −289, respectively. Particular attention was given to Δ f H°(CH 3CO ) = −10.3 ± 1.8 kJ/mol. The current NIST WebBook datum, Δ f H°(CS) = 280.3 kJ/mol, is arguably the best value, being consistent with related thermochemical data. Finally the Δ f H° values for the allylic free radicals CH 2CHCH 2, 174 ± 3 kJ/mol, CH 2CHCH (OH), 4.5 ± 4 kJ/mol, and (CH 2CH) 2 C(OH), 37 ± 4 kJ/mol, derived from experimental data and results of computational chemistry are described, together with some related homolytic bond strengths.

SU‐FF‐T‐322: Miniature TLDs for Use in Beta Dosimetry

Purpose: To demonstrate the production and utility of new miniature thermoluminescent dosimeters (TLDs) for use in electron fields such as those generated by intravascular brachytherapy (IVBT) sources Method and Materials: Square lithium fluoride Harshaw TLD rods were cut into 1×1×0.5mm3 “half‐microcubes” for measurements of dose near a Novoste Beta‐Cath IVBT source pellet. Calibration exposures were performed with a Tracerlab RA‐1 ophthalmic applicator directly traceable to the NIST absorbed dose to water standard. All beta exposures were made in liquid water since it is the reference medium of interest. TLDs were read 24 hours post‐exposure using a Harshaw 3500 planchet reader. TLD mass was tracked throughout the investigation, and individual TLD response characterization factors were determined from exposures before and after each exposure. Results: Radial depth dose measurement (and consequently radial dose function) results show slightly decreased volume averaging effects and increased precision of half‐microcubes compared to standard 1×1×1mm3 microcubes. Half‐microcube measurements also correspond within uncertainty estimates to radiochromic film data and to data published by Soares et al (Med Phys, 25(3), 1998), which is the current NIST standard for IVBT beta sources. Monte Carlo statistical modeling with the MCNP5 transport code served to corroborate the measured radial dose function. Conclusion: Particularly for investigation of beta emitting sources, decreasing the volume over which TLDs average dose provides slightly increased precision in the measurement of relative dose rate at the 2mm reference depth. Precision changes from 12.2% for microcubes to less than 11% for half‐microcubes at the 95% confidence interval. Both sets of measurements also avoid the experimental uncertainty inherent in most current published work by eliminating the conversion to water from data taken in water‐mimicking media. TLDs were used to take advantage of their relatively well‐known response to changes in energy, dose, and dose rate.

Re-Analysis of the Uncertainty of the 0.895 µm Diameter (NIST SRM(®) 1690) and the 0.269 µm Diameter (NIST SRM(®) 1691) Sphere Standards.

The uncertainties of the mean diameters of the nominal 1.0 µm SRM® 1690 polystyrene spheres and of the nominal 0.3 µm SRM® 1691 polystyrene spheres are recomputed using the current NIST Guidelines for computing uncertainty. The revised expanded uncertainty (approximately 95 % confidence level) for SRM® 1690 polystyrene spheres is equal to 0.005 µm compared to previous value of 0.008 µm. The revised expanded uncertainty for SRM® 1691 is equal to 0.004 µm compared to the previous value of 0.007 µm. The major cause of the reduction in the uncertainty for the 1.0 µm spheres is from a decrease in the recomputed uncertainty of the refractive index of the polystyrene spheres. The 1.0 µm spheres were used in calibrating the electron microscope used to size the 0.3 µm spheres, and the reduction in the uncertainty of 1.0 µm SRM® uncertainty was the biggest factor in the decrease in the uncertainty of the 0.3 µm spheres.

On the actual state of industrial quality assurance procedures with regard to (106)Ru ophthalmic plaques.

In radiotherapy of intraocular tumors, e. g., in the case of malign choroid melanomas, episcleral brachytherapy with (106)Ru ophthalmic plaques has proven to be successful. In a study, the authors reported on the discovery of the following shortcomings in industrial quality assurance, which are relevant to therapy, during the course of an internal clinical acceptance test of (106)Ru ophthalmic plaques, manufactured by the company Bebig from Berlin, Germany. This consisted of inconsistent dose rate specifications in the manufacturer's certificate, covering a range of 111% and with the risk of leakage of the plaques. Bebig was called upon to adapt state-of-the-art production methods with regard to (106)Ru ophthalmic plaques. In the meantime, Bebig has modernized production of (106)Ru ophthalmic plaques and adopted all the quality assurance procedures proposed by the authors. Moreover, the requested traceability of the calibration of activity and dose rate of the (106)Ru ophthalmic plaques to standards of the federal authorities in charge of measurement procedures has been implemented. In the year 2002, Bebig updated, among other things, the ASMW (GDR) calibration of the dose rate of the (106)Ru ophthalmic plaques from the years 1987-1989 by a calibration of the NIST (USA). The current NIST calibration, together with the new equipment for the measurement of the depth dose curves, led to the consequence that the new NIST 2001 dose rate values show, in the mean, a deviation of 0.75 times (plaque type CCC) up to 2.06 times (plaque types CCX, CCY, and CCZ) compared to the dose rate values that had been indicated so far in Bebig's certificate, based on the ASMW 1987 calibration. For the 95% confidence interval, Bebig estimated the measurement uncertainty to be +/- 25%. If one takes into consideration the minimal and maximal values in such 95% confidence intervals, it follows that the new NIST 2001 dose rate values deviate between 0.56 times (plaque type CCC) and 2.58 times (plaque types CCX, CCY, and CCZ) from the Bebig certificate (ASMW calibration 1987). As regards leakage, no objections arose in the case of the (106)Ru ophthalmic plaques produced according to the new quality standards. Legislation has to make sure that the use of radioactive material on humans be, among other things, permitted as a matter of principle only, if the dose rate calibration can be traced to standards of a federal authority of measurement procedures. Furthermore, special leakage tests for radiation sources which come into direct contact with body fluids should be established. A historical retrospect reveals that the greatest changes have taken place in the indication of the dose rates of (125)I sources. Since the beginning of the use of (125)I sources in brachytherapy in the late 1960s, the dose rate indications, so far, have had to be reduced in small steps over a period of about 35 years by nearly a factor of 2. As regards the (106)Ru ophthalmic plaques, the NIST 2001 calibration has resulted in a comparable reduction of the dose rate indications of up to a factor of 2 within the period of about several months. Thus, in the previous history of radiotherapy this case must be regarded as unique, because for the first time ever, an urgently needed recalibration has been protracted for such an unduly long period of time.

Heat of Formation of the Hydroperoxyl Radical HOO Via Negative Ion Studies

We present a determination of ΔfH298(HOO) based upon a negative ion thermodynamic cycle. The photoelectron spectra of HOO- and DOO- were used to measure the molecular electron affinities (EAs). In a separate experiment, a tandem flowing afterglow-selected ion flow tube (FA-SIFT) was used to measure the forward and reverse rate constants for HOO- + HC≡CH ⇄ HOOH + HC≡C- at 298 K, which gave a value for ΔacidH298(HOO−H). The experiments yield the following values: EA(HOO) = 1.078 ± 0.006 eV; T0(X̃ HOO − Ã HOO) = 0.872 ± 0.007 eV; EA(DOO) = 1.077 ± 0.005 eV; T0(X̃ DOO − Ã DOO) = 0.874 ± 0.007 eV; ΔacidG298(HOO−H) = 369.5 ± 0.4 kcal mol-1; and ΔacidH298(HOO−H) = 376.5 ± 0.4 kcal mol-1. The acidity/EA thermochemical cycle yields values for the bond enthalpies of DH298(HOO−H) = 87.8 ± 0.5 kcal mol-1 and D0(HOO−H) = 86.6 ± 0.5 kcal mol-1. We recommend the following values for the heats of formation of the hydroperoxyl radical: ΔfH298(HOO) = 3.2 ± 0.5 kcal mol-1 and ΔfH0(HOO) = 3.9 ± 0.5 kcal mol-1; we recommend that these values supersede those listed in the current NIST−JANAF thermochemical tables.

Ab Initio Gas-Phase Acidities of NaH, MgH2, and AlH3

We present ab initio estimates of the gas-phase acidities ΔHacid of the second-row metal hydrides NaH, MgH2, and AlH3. Our estimates are based on frozen-core CCSD(T) calculations using augmented triple- and quadruple-ζ correlation-consistent basis sets that include core polarization functions; these single-point calculations are extrapolated to the complete basis set limit and then adjusted to incorporate core−valence correlation effects, vibrational zero-point energy contributions, and thermal corrections. The final ΔHacid values we obtain at T = 298 K are 345.26 kcal/mol for NaH, 363.83 kcal/mol for MgH2, and 372.93 kcal/mol for AlH3; the estimated uncertainty in these values is ±0.8 kcal/mol. Our results suggest that the current NIST−JANAF recommended bond dissociation energy for NaH is too high by roughly 2 kcal/mol.

The NIST High Accuracy Scale for Absolute Spectral Response from 406 nm to 920 nm.

We describe how the National Institute of Standards and Technology obtains a scale of absolute spectral response from 406 nm to 920 nm. This scale of absolute spectral response is based solely on detector measurements traceable to the NIST High Accuracy Cryogenic Radiometer (HACR). Silicon photodiode light-trapping detectors are used to transfer optical power measurements from the HACR to a monochromator-based facility where routine measurements are performed. The transfer also involves modeling the quantum efficiency (QE) of the silicon photodiode light-trapping detectors. We describe our planned quality system for these measurements that follows ANSI/NCSL Z540-1-1994. A summary of current NIST capabilities based on these measurements is also given.