Tang Ko Cheung, Simon. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 89-91). / Abstracts in English and Chinese. / Chapter 1 --- Theory of Optimal Normal Bases --- p.3 / Chapter 1.1 --- Introduction --- p.3 / Chapter 1.2 --- The minimum number of terms --- p.6 / Chapter 1.3 --- Constructions for optimal normal bases --- p.7 / Chapter 1.4 --- Existence of optimal normal bases --- p.10 / Chapter 2 --- Implementing Multiplication in GF(2m) --- p.13 / Chapter 2.1 --- Defining the Galois fields GF(2m) --- p.13 / Chapter 2.2 --- Adding and squaring normal basis numbers in GF(2m) --- p.14 / Chapter 2.3 --- Multiplication formula --- p.15 / Chapter 2.4 --- Construction of Lambda table for Type I ONB in GF(2m) --- p.16 / Chapter 2.5 --- Constructing Lambda table for Type II ONB in GF(2m) --- p.21 / Chapter 2.5.1 --- Equations of the Lambda matrix --- p.21 / Chapter 2.5.2 --- An example of Type IIa ONB --- p.23 / Chapter 2.5.3 --- An example of Type IIb ONB --- p.24 / Chapter 2.5.4 --- Creating the Lambda vectors for Type II ONB --- p.26 / Chapter 2.6 --- Multiplication in practice --- p.28 / Chapter 3 --- Inversion over optimal normal basis --- p.33 / Chapter 3.1 --- A straightforward method --- p.33 / Chapter 3.2 --- High-speed inversion for optimal normal basis --- p.34 / Chapter 3.2.1 --- Using the almost inverse algorithm --- p.34 / Chapter 3.2.2 --- "Faster inversion, preliminary subroutines" --- p.37 / Chapter 3.2.3 --- "Faster inversion, the code" --- p.41 / Chapter 4 --- Elliptic Curve Cryptography over GF(2m) --- p.49 / Chapter 4.1 --- Mathematics of elliptic curves --- p.49 / Chapter 4.2 --- Elliptic Curve Cryptography --- p.52 / Chapter 4.3 --- Elliptic curve discrete log problem --- p.56 / Chapter 4.4 --- Finding good and secure curves --- p.58 / Chapter 4.4.1 --- Avoiding weak curves --- p.58 / Chapter 4.4.2 --- Finding curves of appropriate order --- p.59 / Chapter 5 --- The performance of 17x bit Elliptic Curve Scalar Multiplication --- p.63 / Chapter 5.1 --- Choosing finite fields --- p.63 / Chapter 5.2 --- 17x bit test vectors for onb --- p.65 / Chapter 5.3 --- Testing methodology and sample runs --- p.68 / Chapter 5.4 --- Proposing an elliptic curve discrete log problem for an 178bit curve --- p.72 / Chapter 5.5 --- Results and further explorations --- p.74 / Chapter 6 --- On matrix RSA --- p.77 / Chapter 6.1 --- Introduction --- p.77 / Chapter 6.2 --- 2 by 2 matrix RSA scheme 1 --- p.80 / Chapter 6.3 --- Theorems on matrix powers --- p.80 / Chapter 6.4 --- 2 by 2 matrix RSA scheme 2 --- p.83 / Chapter 6.5 --- 2 by 2 matrix RSA scheme 3 --- p.84 / Chapter 6.6 --- An example and conclusion --- p.85 / Bibliography --- p.91

by Shum Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 30-32). / Abstracts in English and Chinese. / Acknowledgement --- p.ii / Abstract --- p.iii / □ □ --- p.iv / Chapter 1 . --- Introduction --- p.1 / Chapter 1.1 --- Introduction to topic --- p.1 / Chapter 1.2 --- What is proxy signature? --- p.2 / Chapter 1.3 --- Terminologies in proxy signature --- p.2 / Chapter 1.4 --- Levels of delegation --- p.3 / Chapter 1.5 --- Previous work on Proxy Signature --- p.4 / Chapter 1.6 --- Our Contributions --- p.4 / Chapter 1.7 --- Thesis Organization --- p.4 / Chapter 2. --- Backgroun d --- p.6 / Chapter 2.1 --- Digital Signature --- p.6 / Chapter 2.2 --- Digital Certificate and CA --- p.6 / Chapter 2.3 --- Hash Functions --- p.7 / Chapter 2.4 --- Bit commitment --- p.7 / Chapter 3. --- Brief introduction to Our Result --- p.8 / Chapter 3.1 --- A Proxy Signature Scheme with Proxy Signer Privacy Protection --- p.8 / Chapter 3.2 --- Applications of Proxy Signature --- p.9 / Chapter 4. --- Detail Explanation of Certified Alias and its Application on Proxy Signature --- p.10 / Chapter 4.1 --- Introduction --- p.10 / Chapter 4.2 --- Protecting Signer Privacy Using Certified Alias Definition 4.2.3 --- p.10 / Chapter 4.3 --- Constructing Proxy signature Scheme by Consecutive Execution of Cryptographic Primitives (Scheme CE) --- p.11 / Chapter 4.4 --- Constructing Proxy signature Scheme by Direct Form Equations (Scheme DF) --- p.15 / Chapter 4.5 --- Comparison between scheme CE and scheme DF --- p.19 / Chapter 4.6 --- Chapter Summary --- p.20 / Chapter 5 . --- Applications of Proxy Signature with Proxy Signer Privacy Protection --- p.21 / Chapter 5.1 --- Secure Mobile agent Signature with Itinerary Privacy --- p.21 / Chapter 5.1.1 --- Introduction to Mobile Agent --- p.21 / Chapter 5.1.2 --- "Review on Lee, et al. strong non-designated proxy signature scheme for mobile agents" --- p.21 / Chapter 5.1.3 --- Constructing Signature scheme for Mobile Agent using Proxy signature with Proxy Signer Privacy Protection --- p.22 / Chapter 5.1.4 --- Remarks --- p.23 / Chapter 5.2 --- Group Signature with Unlimited Group Size --- p.24 / Chapter 5.2.1 --- Introduction to group signature --- p.24 / Chapter 5.2.2 --- Constructing group signature scheme using certified alias --- p.24 / Chapter 5.2.4 --- Remarks --- p.26 / Chapter 5.3 --- Chapter Summary --- p.27 / Chapter 6. --- Conclusions --- p.28 / Appendix: Paper derived from this thesis --- p.29 / Bibliography --- p.30

by Yuen Ching Wah. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 61-[63]). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Why use cryptography? --- p.1 / Chapter 1.2 --- Why is authentication important ？ --- p.2 / Chapter 1.3 --- What is the relationship between authentication and digital sig- nature? --- p.3 / Chapter 1.4 --- Why is random number important? --- p.3 / Chapter 2 --- Background --- p.5 / Chapter 2.1 --- Cryptography --- p.5 / Chapter 2.1.1 --- Symmetric key cryptography --- p.5 / Chapter 2.1.2 --- Asymmetric key cryptography --- p.7 / Chapter 2.1.3 --- Authentication --- p.8 / Chapter 2.2 --- Elliptic curve cryptography --- p.9 / Chapter 2.2.1 --- Mathematical background for Elliptic curve cryptography --- p.10 / Chapter 2.3 --- Pseudorandom number generator --- p.12 / Chapter 2.3.1 --- Linear Congruential Generator --- p.13 / Chapter 2.3.2 --- Inversive Congruential Generator --- p.13 / Chapter 2.3.3 --- PN-sequence generator --- p.14 / Chapter 2.4 --- Digital Signature Scheme --- p.14 / Chapter 2.5 --- Babai's lattice vector algorithm --- p.16 / Chapter 2.5.1 --- First Algorithm: Rounding Off --- p.17 / Chapter 2.5.2 --- Second Algorithm: Nearest Plane --- p.17 / Chapter 3 --- Several Digital Signature Schemes --- p.18 / Chapter 3.1 --- DSA --- p.19 / Chapter 3.2 --- Nyberg-Rueppel Digital Signature --- p.21 / Chapter 3.3 --- EC.DSA --- p.23 / Chapter 3.4 --- EC-Nyberg-Rueppel Digital Signature Scheme --- p.26 / Chapter 4 --- Miscellaneous Digital Signature Schemes and their PRNG --- p.29 / Chapter 4.1 --- DSA with LCG --- p.30 / Chapter 4.2 --- DSA with PN-sequence --- p.33 / Chapter 4.2.1 --- Solution --- p.35 / Chapter 4.3 --- DSA with ICG --- p.39 / Chapter 4.3.1 --- Solution --- p.40 / Chapter 4.4 --- EC_DSA with PN-sequence --- p.43 / Chapter 4.4.1 --- Solution --- p.44 / Chapter 4.5 --- EC一DSA with LCG --- p.45 / Chapter 4.5.1 --- Solution --- p.46 / Chapter 4.6 --- EC-DSA with ICG --- p.46 / Chapter 4.6.1 --- Solution --- p.47 / Chapter 4.7 --- Nyberg-Rueppel Digital Signature with PN-sequence --- p.48 / Chapter 4.7.1 --- Solution --- p.49 / Chapter 4.8 --- Nyberg-Rueppel Digital Signature with LCG --- p.50 / Chapter 4.8.1 --- Solution --- p.50 / Chapter 4.9 --- Nyberg-Rueppel Digital Signature with ICG --- p.51 / Chapter 4.9.1 --- Solution --- p.52 / Chapter 4.10 --- EC- Nyberg-Rueppel Digital Signature with LCG --- p.53 / Chapter 4.10.1 --- Solution --- p.54 / Chapter 4.11 --- EC- Nyberg-Rueppel Digital Signature with PN-sequence --- p.55 / Chapter 4.11.1 --- Solution --- p.56 / Chapter 4.12 --- EC-Nyberg-Rueppel Digital Signature with ICG --- p.56 / Chapter 4.12.1 --- Solution --- p.57 / Chapter 5 --- Conclusion --- p.59 / Bibliography --- p.61

Lee, Chin Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 77-82). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

" In this dissertation we explore a new paradigm emerging from the subtleties of cryptographic implementations and relating to theoretical aspects of cryptography. This new paradigm, namely physical variables (PVs), simply describes properties of physical objects designed to be identical but are not due to manufacturing variability. In the first part of this dissertation, we focus our attention on scenarios which require the unique identification of physical objects and we show how Gaussian PVs can be used to fulfill such a requirement. Using this framework we present and analyze a new technique for fingerprinting compact discs (CDs) using the manufacturing variability found in the length of the CDs' lands and pits. Although the variability measured is on the order of 20 nm, the technique does not require the use of microscopes or any advanced equipment. Instead, the electrical signal produced by the photo-detector inside the CD reader will be sufficient to measure the desired variability. We thoroughly investigate the new technique by analyzing data collected from 100 identical CDs and show how to extract a unique fingerprint for each CD. In the second part, we shift our attention to physically parameterized functions (PPFs). Although all the constructions we provide are centered around delay-based physically unclonable functions (PUFs), we stress that the use of the term PUF could be misleading as most circuits labeled with the term PUF are in reality clonable on the protocol level. We argue that using a term like PPFs to describe functions parameterized by a PV is a more accurate description. Herein, we thoroughly analyze delay-PUFs and use a mathematical framework to construct two authentication protocols labeled PUF-HB and HB+PUF. Both these protocols merge the known HB authentication family with delay-based PUFs. The new protocols enjoy the security reduction put forth by the HB portion of the protocol and at the same time maintain a level of hardware security provided by the use of PUFs. We present a proof of concept implementation for HB+PUF which takes advantage of the PUF circuit in order to produce the random bits typically needed for an HB-based authentication scheme. The overall circuit is shown to occupy a few thousand gates. Finally, we present a new authentication protocol that uses 2-level PUF circuits and enables a security reduction which, unlike the previous two protocols, stems naturally from the usage of PVs. "

This dissertation examines the origins of political and scientific commitments that currently frame cryptography, the study of secret codes, arguing that these commitments took shape over the course of the twentieth century. Looking back to the nineteenth century, cryptography was rarely practiced systematically, let alone scientifically, nor was it the contentious political subject it has become in the digital age. Beginning with the rise of computational cryptography in the first half of the twentieth century, this history identifies a quarter-century gap beginning in the late 1940s, when cryptography research was classified and tightly controlled in the US. Observing the reemergence of open research in cryptography in the early 1970s, a course of events that was directly opposed by many members of the US intelligence community, a wave of political scandals unrelated to cryptography during the Nixon years also made the secrecy surrounding cryptography appear untenable, weakening the official capacity to enforce this classification. Today, the subject of cryptography remains highly political and adversarial, with many proponents gripped by the conviction that widespread access to strong cryptography is necessary for a free society in the digital age, while opponents contend that strong cryptography in fact presents a danger to society and the rule of law. I argue that cryptography would not have become invested with these deep political commitments if it had not been suppressed in research and the media during the postwar years. The greater the force exerted to dissuade writers and scientists from studying cryptography, the more the subject became wrapped in an aura of civil disobedience and public need. These positive political investments in cryptography have since become widely accepted among many civil libertarians, transparency activists, journalists, and computer scientists who treat cryptography as an essential instrument for maintaining a free and open society in the digital age. Likewise, even as opponents of widespread access to strong cryptography have conceded considerable ground in recent decades, their opposition is grounded in many of the same principles that defined their stance during cryptography’s public reemergence in the 1970s. Studying this critical historical moment reveals not only the origins of cryptography’s current politics, but also the political origins of modern cryptography.

No description available.

Siu, Pui-Lam. / Thesis submitted in: August 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 104-109). / Abstracts in English and Chinese. / list of figures --- p.5 / list of tables --- p.7 / acknowledgements --- p.8 / abstract --- p.9 / Chapter 1. --- introduction --- p.12 / Chapter 1.1 --- Smart Card --- p.12 / Chapter 1.1.1 --- What is a smart card? --- p.12 / Chapter 1.1.2 --- How is a smart card different from the magnetic stripe card that I carry in my wallet? --- p.13 / Chapter 1.1.3 --- Why are interoperability and enforced standards crucial to widespread adoption of smart cards? --- p.13 / Chapter 1.1.4 --- Contact vs Contactless --- p.14 / Chapter 1.1.5 --- How secure and confidential contactless smart cards are? --- p.14 / Chapter 1.1.6 --- Contactless Smart Card Application Contactless smart cards are widely used in commercial fields as stored-value and secure storage cards --- p.14 / Chapter 1.1.7 --- What are the major benefits that Contactless smart cards offer to consumers? --- p.16 / Chapter 1.2 --- Design Motivation --- p.16 / Chapter 1.3 --- RF Part Interface --- p.17 / Chapter 1.4 --- Potential Advantages of Using Asynchronous Circuit --- p.19 / Chapter 1.5 --- Design Methodology for Asynchronous Circuit --- p.23 / Chapter 1.5.1 --- Difficulty and limitation of asynchronous design --- p.27 / Chapter 1.5.2 --- Asynchronous pipeline --- p.28 / Chapter 2. --- background theory --- p.32 / Chapter 2.1 --- Description of DES --- p.32 / Chapter 2.1.1 --- Outline of the Algorithm --- p.33 / Chapter 2.1.2 --- Initial Permutation --- p.35 / Chapter 2.1.3 --- Key Transformation --- p.35 / Chapter 2.1.4 --- Expansion Permutation --- p.37 / Chapter 2.1.5 --- S-box Substitution --- p.38 / Chapter 2.1.6 --- P-Box Permutation --- p.41 / Chapter 2.1.7 --- Final Permutation --- p.42 / Chapter 2.1.8 --- Decrypting DES --- p.43 / Chapter 2.1.9 --- Security of DES --- p.43 / Chapter 2.1.10 --- Weak Keys --- p.43 / Chapter 2.1.11 --- Algebraic Structure --- p.46 / Chapter 2.1.12 --- Key Length --- p.46 / Chapter 2.1.13 --- Number of Rounds --- p.48 / Chapter 2.1.14 --- Design of the S-Boxes --- p.48 / Chapter 3. --- rf part --- p.50 / Chapter 3.1 --- Power On --- p.51 / Chapter 3.2 --- Power Induction --- p.52 / Chapter 3.3 --- Limiter and Regulator --- p.54 / Chapter 3.4 --- Demodulation --- p.56 / Chapter 3.5 --- Modulation --- p.57 / Chapter 4. --- asynchronous circuit theory --- p.58 / Chapter 4.1 --- Potential Problem of Classical Asynchronous Pipeline --- p.58 / Chapter 4.2 --- The New Handshake Cell --- p.58 / Chapter 4.3 --- The Modified Asynchronous Pipeline Architecture --- p.60 / Chapter 4.4 --- Asynchronous Circuit Comparison --- p.65 / Chapter 5 --- implementation --- p.67 / Chapter 5.1 --- DES Implementation --- p.67 / Chapter 5.1.1 --- Power estimation of the asynchronous DES --- p.70 / Chapter 5.1.2 --- Modified Circuit --- p.73 / Type One --- p.73 / Type two --- p.76 / Chapter 5.1.3 --- Interface --- p.79 / Chapter 5.1.4 --- Shift Unit --- p.80 / Chapter 5.1.5 --- Multiplexer Unit --- p.82 / Chapter 5.1.6 --- Compression Unit --- p.83 / Chapter 5.1.7 --- Expansion Unit --- p.84 / Chapter 5.1.8 --- Xor Unit --- p.85 / Chapter 5.1.9 --- S_box Unit --- p.86 / Chapter 5.1.10 --- P-box unit --- p.88 / Chapter 5.1.11 --- Latch unit --- p.89 / Chapter 5.1.12 --- Transmission Unit --- p.90 / Chapter 5.2 --- Floor Plan Design --- p.90 / Chapter 6. --- result and discussion --- p.93 / Chapter 6.1 --- Simulation Result --- p.93 / Chapter 6.2 --- Measurement --- p.97 / Chapter 6.3 --- Comparison --- p.101 / Chapter 6.4 --- Conclusion --- p.101 / Chapter 7. --- reference --- p.104 / Chapter 8. --- appendix --- p.110 / Chapter 8.1 --- RF Part Implementation --- p.110 / Chapter 8.1.1 --- Full wave rectifying circuit --- p.110 / Chapter 8.1.2 --- "Limiting Circuit," --- p.111 / Chapter 8.1.3 --- Regulator circuit --- p.113 / Chapter 8.1.4 --- Demodulation circuit --- p.113 / Chapter 8.1.5 --- Simulation of the RF part --- p.115 / Chapter 8.2 --- New Technology for Designing a RF Interface --- p.117 / Chapter 8.2 --- Block Diagrams --- p.118

In The Second Theory of Cryptography Conference (TCC 2005), Boneh, Goh, and Nissim proposed a new structure of bilinear groups that have a composite order and a new cryptosystem which is intractable on a decisional problem over the subgroup in such structure [BGN05]. Their proposal, which referred to as the BGN cryptosystem by researchers, receive much attention and is quickly followed by two publications in CRYPTO'05 [BI05, OI05]. / In this thesis, the author performs in-depth study of the BGN public-key cryptosystem and existing literatures on its applications. The author observes two properties of BGN, namely the indistinguishability of the BGN ciphertexts of sum and product of two messages, and the verifiability of elements from composite prime subgroups in BGN settings. The author further proposes three new applications of BGN, namely the protocols for authentication, oblivious transfer, and proof-of-visit respectively. / The BGN cryptosystem is a dual homomorphic public-key cryptosystem that enables the evaluation of 2-DNF (disjunctive normal form) formulas on ciphertexts. In their work, Boneh et. al. also presented three applications, namely private information retrieval with reduced computational complexity, an e-voting system without non-interactive zero knowledge proofs, and a protocol for universally verifiable computation. Few number of works also produced from the BGN public-key system, include non-interactive zero-knowledge proof (NIZK), obfuscated ciphertext mixing, and signature. / Chan Yuen Yan. / "June 2006." / Adviser: Victor K. Wei. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6498. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 85-100). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

In the presented work we focus on both implementation and protocol of the voice over IP application Skype. We analyse several versions of Skype clients and deduce inner workings of the Skype protocol. We present details about the cryptographic primitives used by the Skype clients and their impact on the security of the communication. We emphasize several places of suspicious leaks of the internal states of random generators and deduce rules for the detection of the Skype traffic on the firewall. In the end, we mention a simple enhancement of the current Skype clients that, in practice, can detect an ongoing eavesdropping.