CRYPTANALYSIS AND IMPROVEMENT OF A PROXY SIGNATURE WITH MESSAGE RECOVERY USING SELF-CERTIFIED PUBLIC KEY

Chande, Manoj Kumar,Lee, Cheng-Chi Korean Mathematical Society 2016 대한수학회보 Vol.53 No.4

Combining the concept of self-certified public key and message recovery, Li-Zhang-Zhu (LZZ) gives the proxy signature scheme with message recovery using self-certified public key. The security of the proposed scheme is based on the discrete logarithm problem (DLP) and one-way hash function (OWHF). Their scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, their scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signer. In this paper, it is shown that in their signature scheme a malicious signer can cheat the system authority (SA), by obtaining a proxy signature key without the permission of the original signer. At the same time malicious original signer can also cheat the SA, he can also obtain a proxy signature key without the permission of the proxy signer. An improved signature scheme is being proposed, which involves the remedial measures to get rid of security flaws of the LZZ et al.'s. The security and performance analysis shows that the proposed signature scheme is maintaining higher level of security, with little bit of computational complexity.

Evaluation of Bond Strength of Dentin Adhesive at Dry and Moist Dentin-Resin Interface: An In-vitro Study

Keyur Pankaj. Chande,Narendra U. Manwar,Manoj G. Chandak 대한예방치과학회 2013 International Journal of Clinical Preventive Denti Vol.9 No.4

Objective: The aim of this study is to compare the effect of surface moisture on dentinal tensile bond strength. Methods: Eighty freshly extracted caries free Mandibular first molars were selected. The specimens were randomly divided into four groups of 20 teeth each. Occlusal surface were ground by diamond disc till all occlusal enamel is removed. After treating the occlusal surface of specimens with 37% orthophosphoric acid for 15 sec, specimens were divided into 4 groups namely. Group I (Over wet), Group II (Blot Dry), Group III (One Second Dry) and Group IV (Over Dry). Each group was treated with single bond adhesive (3M ESPE). Composite cylinders were build up using Teflon moulds and cured. Tensile bond strength was tested using INSTRON universal testing machine. The results were analysed statistically. Results: The tensile bond strength values were highest in Group II (Blot dry) and statistically significant. Conclusion: Blot drying after etching provided better bond strength.

Cryptanalysis and improvement of a proxy signature with message recovery using self-certified public key

Manoj Kumar Chande 대한수학회 2016 대한수학회보 Vol.53 No.4

Combining the concept of self-certified public key and message recovery, Li-Zhang-Zhu (LZZ) gives the proxy signature scheme with message recovery using self-certified public key. The security of the proposed scheme is based on the discrete logarithm problem (DLP) and one-way hash function (OWHF). Their scheme accomplishes the tasks of public key verification, proxy signature verification, and message recovery in a logically single step. In addition, their scheme satisfies all properties of strong proxy signature and does not use secure channel in the communication between the original signer and the proxy signer. In this paper, it is shown that in their signature scheme a malicious signer can cheat the system authority (SA), by obtaining a proxy signature key without the permission of the original signer. At the same time malicious original signer can also cheat the SA, he can also obtain a proxy signature key without the permission of the proxy signer. An improved signature scheme is being proposed, which involves the remedial measures to get rid of security flaws of the LZZ et al.'s. The security and performance analysis shows that the proposed signature scheme is maintaining higher level of security, with little bit of computational complexity.

Effect of Chelating Agents and Irrigants on Mineral Content of Root Canal Dentin: An In Vitro Study

Keyur Pankaj Chande,Narendra U Manwar,Manoj G Chandak,Jyoti Lokade,Sneha R Chandak 대한예방치과학회 2014 International Journal of Clinical Preventive Denti Vol.10 No.3

Objective: To evaluate and compare ex vivo the decalcifying effect of 17% ethylenediaminetetraacetic acid (EDTA), 15% citric acid, 37% phosphoric acid and 5.25% sodium hypochlorite on root canal dentin. Methods: Two 2-mm-thick slices were cut from the coronal third of the root of 24 human incisors. Each slice was sectioned into two equal parts. Specimens were assigned to one of four groups (n=24) for immersion in 20 ml of either 17% EDTA, or 15% citric acid, 37% phosphoric acid or 5.25% NaOCl, for three time periods (5, 10, and 15 minutes). The concentration of Ca2+ extracted from the dentine was measured by mass spectrophometry.The amount of calcium extracted was analysed using the Kruskal-Wallis test for global comparisons and the Mann-Whitney U-test for pairwise comparisons. Results: In the three time periods, 17% EDTA and 15% citric acid extracted the largest amount of calcium, with no significant differences between them. The 5.25% NaOCl solution extracted significant amounts of calcium, whereas 17% EDTA extracted 9.3 mg of the calcium in the first 5 min, and 15% citric acid and 37% phosphoric acid had a similar pattern of calcium removal (2.06 mg and 1.82 mg in first 5 minutes, respectively). Conclusion: Solutions of 15% EDTA, 15% citric acid and 5% phosphoric acid decalcify root dentine, with most calcium extracted during the first 5 minutes of action. The efficacy of 15% citric acid and 17% EDTA solutions was significantly greater than that of 37% phosphoric acid solution at each time period (5, 10 and 15 minutes).

Multiplex Real-time PCR Assay for the Detection of all Chlamydia Species and Simultaneous Differentiation of C. psittaci and C. pneumoniae

Wolff Bernard J.,Gaines Anna,Conley Andrew B.,Norris Emily,Rishishwar Lavanya,Chande Aroon T.,Yang Eungi,Diaz Maureen H.,Winchell Jonas M. 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.4

We developed and assessed the performance of a new multiplex real-time PCR assay for the detection of all Chlamydia species and simultaneous differentiation of Chlamydia psittaci and Chlamydia pneumoniae—two important human respiratory pathogens—in human clinical specimens. Next-generation sequencing was used to identify unique targets to design real-time PCR assays targeting all Chlamydia species, C. psittaci, and C. pneumoniae. To validate the assay, we used a panel of 49 culture isolates comprising seven C. psittaci genotypes, eight C. pneumoniae isolates, seven other Chlamydia species, and 22 near-neighbor bacterial and viral isolates, along with 22 specimens from external quality assessment (EQA) panels and 34 nasopharyngeal and oropharyngeal swabs and cerebrospinal fluid, stool, and sputum specimens previously identified as positive or negative for C. psittaci or C. pneumoniae. The assays were 100% specific, with limits of detection of 7.64– 9.02 fg/μL. The assay results matched with historical assay results for all specimens, except for one owing to the increased sensitivity of the new C. psittaci assay; the results of the EQA specimens were 100% accurate. This assay may improve the timely and accurate clinical diagnosis of Chlamydia infections and provide a greater understanding of the burden of disease caused by these agents.

다차원 공간내에서 움직이는 등방성매질의 R L C

홍창희,문태정,하영철 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1

From the point of vew of the constitutive relations, electromagnetic waves are studied, with attention given to the behavior inside media that are lenear and isotropic. In describing physical laws of nature, equation are form invariant with respect to uniformly moving observers are called Lorentz covariant. Written in tensor notation, both Maxwell equations and constitutive relations are manifestly covariant. The Lorentz covariant description of the constitutive relations is called bianisotropic. The transformation of field quantities and the constitutive relations from one frame to another is derived from Loretz transformation for 4-dimmension space. Isotropic media, when viewed from a moving frame, became bianisotropic. Problems involving one moving medium can usually be solved in the rest frame of teh medium, with results transformed back to the observers rame of reference. As the final result, we have, the conductivity variation rates are r, the permittivity variation rates are determined by (83), and the permeability variation rates are determined by(84).

Blood biochemical profile of four fast-growing broiler strains under high ambient temperature

Chand, Naila,Naz, Shabana,Rehman, Ziaur,Khan, Rifat Ullah The Korean Society for Applied Biological Chemistr 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.3

The present study was carried out to evaluate the effect of optimum and high ambient temperatures on biochemical parameter of four broiler strains. Broiler chicks (n = 242) of four different commercial strains (Ross, Hubbard, Cobb and Arber Acer) on day 15 were divided into two groups: thermo-neutral zone (TN) group and high ambient temperature zone (HAT) group. Chicks in TN group were housed at constant room temperature ($25^{\circ}C{\pm}2^{\circ}C$ and RH $65{\pm}5%$) while chicks in HAT group were kept under HAT of summer. Chicks in each group were further divided into four subgroups, i.e., TN-Ross, TN-Hubbard, TN-Cobb, TN-Arber Acer and HAT-Ross, HAT-Hubbard, HAT-Cobb, HAT-Arber Acer. Each subgroup was further subdivided into four replicates having ten chicks per replicate. Blood was collected on day 21 and 42. Mean serum aspartate aminotransferase (AST), alanine amino transaminase (ALT), alkaline phosphates (ALP), glucose, cholesterol, triglyceride, and low-density lipoprotein (LDL) were significantly higher (P<0.05) in HAT group, while total serum protein and high-density lipoprotein (HDL) were significantly higher (P<0.05) in TN group. In TN zone group, significantly (P<0.05) lower AST, ALT, glucose, cholesterol, triglyceride, and LDL and significantly (P<0.05) higher HDL and total protein were recorded for Cobb and Hubbard strains. In HAT zone group, significantly (P<0.05) lower AST, ALT, glucose, cholesterol, triglyceride, and LDL and significantly (P<0.05) higher HDL and total protein were recorded for Ross and Arber Acer strains. The findings of the present study suggested that Ross and Arber Acer strains were more tolerant to summer HAT of tropical areas than Cobb and Hubbard, while Cobb and Hubbard strains were more effective in TN environment.

Protective Effects of Milk Thistle (Silybum marianum) against Aflatoxin B1 in Broiler Chicks

Chand, N.,Muhammad, Din,Durrani, F.R.,Qureshi, M. Subhan,Ullah, Sahibzada S. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.7

Aflatoxin-contaminated feed cause mortality, suppression of the immune system, reduced growth rates and losses in feed efficiency. This research study was planned to investigate the immunomodulatory and growth promoting effect of milk thistle as feed additive against aflatoxin $B_1$ in broiler chicks at NWFP Agricultural University Peshawar, Pakistan. Two hundred and forty (240) day old broilers chicks were randomly assigned into four major groups AfF, aflatoxin free feed; Aflatoxin $B_1$ was present in the feed at the levels of 80-520 ${\mu}g/kg$ of the feed in the remaining three groups. Aflatoxin contaminated feed was provided for 5 weeks. Group AfB was supplemented with toxin binder "Mycoad" at 3 g/kg of feed and group AfT was supplemented with milk thistle at10 g/kg of feed. Each group was further sub divided into two sub-groups, vaccinated against ND (Newcastle disease), IB (Infectious bronchitis) and IBD (Infectious bursal diseases) according to recommended schedule of vaccination or non vaccinated. Each sub group carried three replicates with 10 chicks per replicate. Chicks were reared in pens in an open sided house. Supplementary heat was provided to all the chicks during brooding period. Mean body weight gain and dressing percentage were significantly (p<0.05) higher in group AfF, followed by AfT, AfB and Af. Weight gain and dressing percentage was the same in group AfB and AfT, while it was significantly lower in group Af. Feed intake, breast, thigh and leg weight were found significantly (p<0.05) higher in group AfF, followed by AfB, AfT and Af. Significantly lower (better) FCR value was recorded in group AfT. Water intake was significantly (p<0.05) higher in group AfT and AfF as compared to other groups. Mortality was significantly (p<0.05) higher in group Af. Mean bursa and thymus weights were found significantly (p<0.05) higher in group AfF, AfB and AfT followed by Af, while higher spleen weight was recorded in group AfT. Mean antibody titer against ND, IB and IBD was significantly (p<0.05) higher in group AfT, as compared to other groups. It is concluded that milk thistle at 10 g/kg of feed could effectively be utilized as immunostimulant and growth promotant in the presence of immunosuppressant aflatoxin $B_1$ in the feed.

The Theme of Self-Realization in Measure for Measure

Chand, Kee-won 연세대학교 영어영문학과 1982 영어영문학연구 Vol.6 No.-

Ⅰ. Measure for Measure is a play which has given rise to an extraordinary diversity of critical opinions and interpretations It can be read as being "dark, serious and ironical,"1) or it can be read as showing a restoration of order, ending on a note of mercy, reconciliation and love Coleridge comments on the play "The play is to me the most painful part of his genuine works The comic and tragic parts equally border on the hateful-the one being disgusting the other being hateful."2) But contemporary critics admit this play as a genuine work of Shakespeare Furthermore, many critics argue that in Measure for Measure Shakespeare has dealt with sin and its forgiveness in a spirit of exalted Chnstianity.3) Though the play raises many problems as a `problem play,' I would like to examine this play in terms of the theme of mercy and forgiveness When we consider the play along this line of thought, we find that some characters of the play attain self-realization in the course of the action Ⅱ. The whole action of the play stems from the Duke's decision to experiment with the properties of government. He subjects Angelo, Isabella, and the entire city of Vienna to a test, the purpose of which is to determine the best means of regulating man's sinful nature6) As many critics have pointed out, the role of the Duke is very ambiguous sometimes as Providence, sometimes as a type of the good ruler, in Act III he appears as one in disguise, and acts as instigator and director of the action. In this essay, I will consider the Duke as a judge of all test which reveals man's concealed nature and helps the characters to attain selfknowledge. Ⅲ. As I have argued so far, each case of self-realization is attained through inner acceptance of God's mercy and social involvement and through realization of the-commom bond of humanity. In the final scene of public trial, the Duke "like power divine"(V.i 367) sits upon the scat of judgement, and prepares to deal with the corruption which he has seen "boil and bubble" (V.i. 316) in Vienna. When Angelo's flaw is made public, Angelo is brought to his knees in repentance, and says "Immediate sentence, then, and sequence death/ Is all the grace I beg" (V.i 371-372) Seeing his trespasses in the light of day, Angelo cannot bring himself to asking for mercy or grace. He feels that he must die for his sin.

추운 겨울밤

Chand, Prem,이은구 한국외국어대학교 학생통역협회 1983 외대통역협회지 Vol.1 No.1