52 Things People Should Know To Do CryptographyWhat is this?Cryptography is a highly interdiscplinary area; calling on expertise in Pure Mathematics, Computer Science and Electronic Engineering. At Bristol we cover the full range of these topics and as such our students come with a variety of backgrounds and need to understand a diverse range of topics. Students starting can often feel overwhelmed by the types of knowledge that they feel they need to know; not knowing what they need to remember and what they should not bother remembering. To aid you, below we have collected a set of 52 short points of things we think that at the end of the first year of a PhD all students should have some familiarity with. There is one point for every week of the year. If you know these things then following seminars, study groups and conference talks will be much easier. It will also help in putting your own work into context. Some of these are somewhat advanced topics, some of these are what one would pick up in certain undergraduate courses. This is deliberate since some are about being a cryptographer, and some are to address the fact that students start with different backgrounds. If at the end of the first year you know the answers to ninety percent of the things we list then you should find that you will get more out of the conferences and talks you attend in your second year. In addition it will be easier to talk to cryptographers (who may be future employers) from other institutions since you will be able to converse with them using a common language. Almost all of the following are discussed in our undergraduate cryptography courses. By each section we give a reference to places where the definitions can be found, or where to start your reading. The list of references can be found at the bottom. Not all answers can be found in the references cited, but they should give you a place to start looking. Computer Engineering ( ) What is the difference between the following? A general-purpose processor. A general-purpose processor with instruction-set extensions. A special-purpose processor (or co-processor). An FPGA. What is the difference between a multi-core processor and a vector processor? Estimate the relative computational and storage capabilities of a smart-card a micro-controller (i.e. a sensor node) an embedded or mobile computer (e.g., a mobile phone or PDA) a laptop- or desktop-class computer. Theoretical Computer Science ( ) What is meant by the complexity class P? What is meant by the complexity class NP? How can we interpret NP as the set of theorems whose proofs can be checked in polynomial time? How does randomness help in computation, and what is the class BPP? How does interaction help in computation, and what is the class IP? What are Shannon's definitions of entropy and information?Mathematical Background ( ) What is the difference between the RSA and the Strong-RSA problem? What are the DLP, CDH and DDH problems? What is the elliptic curve group law? Outline the use and advantages of projective point representation. What is a cryptographic pairing?Basic (Practical or Deployed) Cryptographic Schemes and Protocols ( ) Describe the key generation, encryption and decryption algorithms for RSA-OAEP and ECIES. Describe the key generation, signature and verification algorithms for DSA, Schnorr and RSA-FDH. Describe and compare the round structure of DES and AES. Draw a diagram (or describe) the ECB, CBC and CTR modes of operation. Describe the Shamir secret sharing scheme. How are Merkle-Damgaard style hash functions constructed?Cryptographic Implementation Details ( ) How does the CRT method improve performance of RSA? How do you represent a number and multiply numbers in Montgomery arithmetic? Write a C program to implement Montgomery arithmetic. Describe the binary, m-ary and sliding window exponentiation algorithms. Describe methods for modular reduction using "special" primes that define GF(p) and GF(2^n). Describe the NAF scalar multiplication algorithm.Security Definitions and Proofs ( ) What is the IND-CCA security definition for symmetric key encryption? What is the IND-CCA security definition for public key encryption? What is the UF-CMA security definition for digital signatures? Roughly outline the BR security definition for key agreement? Give one proof of something which involves game hopping Outline the difference between a game based and a simulation based security definition.Mathematical Attacks ( ) How does the Bellcore attack work against RSA with CRT? Describe the Baby-Step/Giant-Step method for breaking DLPs Give the rough idea of Pollard rho, Pollard "kangaroo" and parallel Pollard rho attacks on ECDLP. What is meant by index calculus algorithms? Roughly outline (in two paragraphs only) how the NFS works.Practical Attacks ( ) What is the difference between a covert channel and a side-channel? What is the difference between a side-channel attack and a fault attack? What is usually considered the difference between DPA and SPA? Are all side channels related to power analysis? Look at your C code for Montgomery multiplication above; can you determine where it could leak side channel information? Describe some basic (maybe ineffective) defences against side channel attacks proposed in the literature for AES. Describe some basic (maybe ineffective) defences against side channel attacks proposed in the literature for ECC. Describe some basic (maybe ineffective) defences against side channel attacks proposed in the literature for RSA.Advanced Protocols and Constructions ( ) What is the Fiat-Shamir transform? What does correctness, soundness and zero-knowledge mean in the context of a Sigma protocol? What is the purpose and use of a TPM? Describe the basic ideas behind IPSec and TLS. What is the BLS pairing based signature scheme? What is the security model for ID-based encryption, and describe one IBE scheme. Pick an advanced application concept such as e-Voting, Auctions or Multi-Party Computation. What are the rough security requirements of such a system? Further Reading Nigel's book is deliberately informal and tries to give quick flavours of what is important in theory and practice. The Katz Lindell book is a better formal introduction to modern theoretical cryptography but it is less good in its treatment of what is important in the real world (e.g. the coverage of AES, ECC, implementation, etc is quite limited). Goldreich's two volume book is a very good introduction to the deep theory, but deliberately does not cover practical cryptography. Elisabeth's DPA book is the best introduction to all things about side-channels. Dan's book is a good starting place for computer architecture and learning VHDL. Goldreich's book on complexity theory is a good place to start. Its approach is much more down-to-earth and sensible than other approaches (i.e. P vs NP is presented in terms of is it easier to check or find proofs?)
看了普林斯顿大学主页的介绍，有一点很让我很惊讶。这个世界第四古老的大学，居然只有1132个员工，7000多个学生。这在中国也就是一个专科学校的规模。可普林斯顿的产出与排名均在世界前三名内。 Princeton University is a vibrant community of scholarship and learning that stands in the nation's service and in the service of all nations. Chartered in 1746, Princeton is the fourth-oldest college in the United States. Princeton is an independent, coeducational, nondenominational institution that provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences and engineering. As a world-renowned research university, Princeton seeks to achieve the highest levels of distinction in the discovery and transmission of knowledge and understanding. At the same time, Princeton is distinctive among research universities in its commitment to undergraduate teaching. Today, more than 1,100 faculty members instruct approximately 5,000 undergraduate students and 2,500 graduate students. The University's generous financial aid program ensures that talented students from all economic backgrounds can afford a Princeton education. Academics Faculty, including full time, part time and visiting: 1,132 (spring 2010) Undergraduate student to faculty ratio: 6:1 Departments: 34 Interdisciplinary certificate programs: 46 Schools within the University: School of Architecture, School of Engineering and Applied Science, Woodrow Wilson School of Public and International Affairs Library holdings: More than 13 million in 11 libraries Students Student enrollment: 7,494 total; 5,044 undergraduate; 2,450 graduate (2009-10) Undergraduate admission rate in 2010-11: 8.8 percent Undergraduate students on financial aid: 60 percent Average financial aid grant for the class of 2014: $36,650 Students from more than 98 countries American minorities make up approximately 37 percent of the undergraduate student body
以色列一科学家质疑100多篇关于Runx3的文章。Science 28 October 2011: Vol. 334 no. 6055 pp. 442-443 DOI: 10.1126/science.334.6055.442 NEWS ANALYSIS CANCER RESEARCH Dispute Over Tumor Suppressor Gene Runx3 Boils Over Dennis Normile A key, decade-old finding by a prominent Japanese cancer researcher based at the National University of Singapore (NUS) is under fire from a group in Israel that calls it “irreproducible.” If the challenge overturns the original work, which identified a gene called Runx3 as a tumor suppressor, hundreds of scientific papers might be affected. The dispute began with a scientific disagreement almost a decade ago and escalated sharply after the group in Israel filed a formal complaint earlier this fall with NUS, which recently launched an investigation. View larger version: In this page In a new window Confident. Yoshiaki Ito says his designation of Runx3 as a tumor suppressor will stand up to scrutiny. CREDIT: D. NORMILE/ SCIENCE The challenge comes from a group led by Yoram Groner of the Weizmann Institute of Science in Rehovot, Israel. In 2001, Groner's group published a paper in Mechanisms of Development cataloging, among other things, the tissues in which Runx3 is expressed; they did not find it in gastrointestinal tract epithelium. Little was then known about Runx3 's function. A year later, a team of researchers at institutes in Japan and South Korea led by Yoshiaki Ito, then at Kyoto University, published a paper in Cell claiming that Runx3 is expressed in gastrointestinal tract epithelium and that it functions as a tumor suppressor, concluding that “a lack of Runx3 function is causally related to the genesis and progression of human gastric cancer.” The two groups have defended their clashing results ever since. Groner and his colleagues launched their recent salvo in a paper first published online on 8 August by EMBO Molecular Medicine . In it, they claim that “using seven different stringent measures, we herein provide compelling evidences that not only directly, definitely and unequivocally rule out the possibility that Runx3 is expressed in , but also challenge the notion that Runx3 functions in this tissue as a TSG .” The team reported that it tried but failed to replicate the results of the original Cell paper using the same line of knockout mice Ito's team used. In supplemental material published with the EMBO Molecular Medicine paper, Groner's team lists 286 papers that the team says are based at least partly on the 2002 Cell paper by Ito's group. “None of the previous reports has gone back and carefully examined, using a variety of highly stringent measures, whether Runx3 is actually expressed in the tissue in which it was reported to be expressed,” the team writes. Groner's group claims that 145 of those papers rely on an analysis of the status of Runx3 DNA methylation that “does not and cannot represent a proof or even a credible indication/suggestion that the methylated gene is a TSG.” Other papers, according to the challengers, got unreliable results, and some failed to find Runx3 expression in the gastrointestinal tract epithelium. At the request of an official at NUS, Groner says, he filed a formal complaint with the university. The Ito group's results “are irreproducible, and because of the nature of the irreproducibility, and they cannot be reproduced in the original mice that they are supposed to be reproduced in, the only conclusion could not possibly be reached in the first place,” Groner says. The university confirmed in a statement that Groner “has contacted us and an inquiry is in process according to the university's research integrity code” but declined further comment. The inquiry came to light when Singapore's Straits Times newspaper reported it on 19 October. In response, Ito says, “I strongly believe that scientific disagreements can be solved only in the scientific arena.” Shortly after publishing the Cell paper in 2002, Ito and several members of his team moved to the Institute of Molecular and Cell Biology, part of Singapore's Agency for Science, Technology and Research, and later to the Cancer Science Institute of Singapore at NUS. Ito concedes that his group cannot now replicate a key experiment from the 2002 Cell paper in the line of mice originally used. This is an “embarrassment,” he says. The mouse line has been bred continuously for 10 years; he says it's possible that the marker gene inserted into the genome could have been deleted or silenced. In a long rebuttal submitted to EMBO Molecular Medicine and provided to Science , Ito points to other studies supporting his group's work, particularly their own 2005 paper in Cancer Research finding Runx3 in the human gastrointestinal tract, a finding he says has been replicated by at least one other group. Groner's team did not address these results, Ito says, adding that Groner's EMBO Molecular Medicine paper “is full of flaws.” Many Runx researchers find the latest twist in the saga unfortunate. “Differences in gene-targeting strategies and quirks of antibody reactivity could not be excluded as the source of discrepancies” between the two groups, says James Neil, a cancer researcher who has studied the Runx genes for over 10 years at the University of Glasgow in the United Kingdom. He says the Groner group's recent results “are impressively negative.” He adds: “Proving a negative is not an easy task in biology.” Still, the findings, although not conclusive, “may have shifted the burden of proof towards those who believe Runx3 to be a tumor suppressor.” View larger version: In this page In a new window Skeptical. Yoram Groner says key Runx3 findings are irreproducible. CREDIT: YIVSAM AZGAD, THE WEIZMANN INSTITUTE MAGAZINE If Groner's conclusions hold up, “it will have a significant bearing on our interpretation of the role of Runx3 in epithelial cancers,” Neil says. He explains that researchers have been receptive to the concept of Runx3 as a tumor suppressor because of several lines of evidence, particularly the extensively replicated observation that Runx3 's promoter is methylated in epithelial and other cancers, indicating that the promoter and therefore the gene were switched off. He says this is supportive circumstantial evidence but “not definitive evidence of a causal role” for Runx3 . Just what the results could mean for the 286 papers Groner's group identifies as based on the Ito team's 2002 Cell paper is not clear. According to the supplemental material, the Groner team searched PubMed using the terms “Runx3” and “cancer” and evaluated papers returned for relevancy. But an author of 18 of those papers, Shuji Ogino, a cancer researcher at the Dana-Farber Cancer Institute and Harvard Medical School in Boston, says his papers shouldn't be on the list. They use Runx3 simply as a biological marker and are not focusing on its function at all. “My papers are not based on that Cell paper,” he says. Neil thinks the only way to resolve the impasse is by conducting experiments with knockout mice in which Runx3 is specifically inactivated in epithelial cells. Ito says he is now laying plans to develop the required mice, but that will take time. Meanwhile, Neil says, “I suspect that most in the Runx community remain open-minded.”
1.This moment will nap ,you will have a dream; But this moment study,you will interpret a dream. 此刻打盹，你将做梦；此刻学习，你将圆梦。 2. I leave uncultivated today,was precisely yesterday perishestomorrow which person of the body implored. 我荒废的今日，正是昨日殒身之人祈求的明日。 3.Thought is already is late,exactlly is the earliest time. 觉得为时已晚时，恰恰是最早的时候。 4. Not matteer of the today will drog tomorrow. 勿将今日之事拖到明日。 5.Time the study pain is temporary,has not learned the pain is life-long. 学习时的痛苦是暂时的，而没学到的痛苦是终身的。 6. Studies this matter,lacks the time,butis lacks diligently. 学习这件事不是缺少时间，而是缺少努力。 7. Perhaps happiness does not arrange the position,but succeeds mustarrange the position. 幸福或许不排名次，而成功必排名次。 8. The study certainly is not the life complete.But,sincecontinually life part of-studies also is unable to conquer, what but also can make? 学习并不是人生的全部。但，既然连人生的一部分——学习也无法征服，还能做什么呢？ 9. Please enjoy the pain which is unable to avoid. 请享受无法回避的痛苦。 10. Only has compared to the others early,diligently diligently ,canfeel the successful taste. 只有比别人更早、更勤奋的努力，才能尝到成功的滋味。 11. Nobody can casually succeed,it comes from the thorough self-control and the will. 没有人能随随便便成功，他来自彻底的自我管理和意志。 12. The time is passing. 时间在流逝.... 13. Now drips the saliva,will become tomorrow the tear. 现在淌的哈喇子，将成为明天的眼泪。 14. The dog equally study,the gentleman equally plays. 狗一样的学。绅士一样的玩。 15. Today does not walk,will have to ran tomorrow. 今天不走，明天就不得不跑。 16. The investment future person willl be,will be loyal to the realityperson. 投资未来的人是忠于现实的人。 17. The education level represents the income. 教育程度代表收入。 18. One day, has not been able again to come. 一天过完，不会再来。 19. Even if the present,the match does not stop changes the page. 即便是现在，对手也没有停止翻书本。 20. Has not been difficult, then does not have attains. 没有艰辛，便没有收获。
B.W. Li, Y.S. Sun , D.W. Zhang. Chebyshev collocation spectral methods for coupled radiation and conduction in a concentric spherical participating medium. Journal of Heat Transfer , 2009, 131(6): 062701-9. download Abstract: The Chebyshev collocation spectral method for coupled radiative and conductive heat transfer in concentric spherical participating medium is introduced and formulated. The angular dependence of the problem is discretized by conventional discrete ordinates method, and the space dependence is expressed by Chebyshev polynomial and discretized by collocation spectral method. Due to the exponential convergence of the spectral methods, very high accuracy can be obtained even using a small resolution (i.e., number of collocation points) for present problems. Comparisons between the solutions from Chebyshev collocation spectral-discrete ordinates method (SP-DOM) with available numerical or exact solutions in references indicate that the SP-DOM for the combination of radiation and conduction in concentric spherical participating medium is accurate and efficient.
L. Zhang, J.M. Zhao, L.H. Liu . Finite Element Method for Modeling Radiative Transfer in Semitransparent Graded index Cylindrical Medium. Journal of Quantitative Spectroscopy and Radiative Transfer . 2009, 110: 10851096. download Abstract: Both Galerkin finite element method (GFEM) and least squares finite element method (LSFEM) are developed and their performances are compared for solving the Radiative Transfer Equation of Graded index medium in Cylindrical coordinate system (RTEGC). The angular redistribution term of the RTEGC is discretized by finite difference approach and after angular discretization the RTEGC is formulated into a discrete-ordinates form, which is then discretized based on Galerkin or least squares finite element approach. To overcome the RTEGC-led numerical singularity at the origin of cylindrical coordinate system, a pole condition is proposed as a special mathematical boundary condition. Compared with the GFEM, the LSFEM has very good numerical properties and can effectively mitigate the nonphysical oscillation appeared in the GFEM solutions. Various problems of both axisymmetry and nonaxisymmetry, and with medium of uniform refractive index distribution or graded refractive index distribution are tested. The results show that both the finite element approaches have good accuracy to predict the radiative heat transfer in semitransparent graded index cylindrical medium, while the LSFEM has better numerical stability.
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