Signature Size Research Articles

The 'Write' Size of Trading Behavior: Overconfidence, Prices, and Bubbles in Experimental Asset Markets

This study analyzes the role that overconfidence plays in investor trading behavior. Using a unique measure of confidence (signature size) with an experimental economics approach, we find that those who are more confident bid significantly higher for assets in simulated trading exercises. This is consistent with previous research that overconfident individuals put too much weight on private signals and/or valuations. We further find that markets with a higher percentage of overconfident individuals experience more mispricing and more overpricing.

Why breast cancer signatures are no better than random signatures explained

Random signature superiority (RSS) occurs when random gene signatures outperform published and/or known signatures. Unlike reproducibility and generalizability issues, RSS is relatively underexplored. Yet, understanding it is imperative for better analytical outcome. In breast cancer, RSS correlates strongly with enrichment for proliferation genes and signature size. Removal of proliferation genes from random signatures reduces the predictive power of random signatures. Almost all genes are correlated to a certain extent with the proliferation signature, making complete elimination of its confounding effects impossible. RSS goes beyond breast cancer, because it also exists in other diseases; it is especially strong in other cancers in a platform-independent manner, and less severe, but present nonetheless, in nonproliferative diseases.

Predictive Gene Signatures Determine Tumor Sensitivity to MDM2 Inhibition.

Early clinical trials using murine double minute 2 (MDM2) inhibitors demonstrated proof-of-concept of p53-induced apoptosis by MDM2 inhibition in cancer cells; however, not all wild-type TP53 tumors are sensitive to MDM2 inhibition. Therefore, more potent inhibitors and biomarkers predictive of tumor sensitivity are needed. The novel MDM2 inhibitor DS-3032b is 10-fold more potent than the first-generation inhibitor nutlin-3a. TP53 mutations were predictive of resistance to DS-3032b, and allele frequencies of TP53 mutations were negatively correlated with sensitivity to DS-3032b. However, sensitivity to DS-3032b of TP53 wild-type tumors varied greatly. We thus used two methods to create predictive gene signatures. First, by comparing sensitivity to MDM2 inhibition with basal mRNA expression profiles in 240 cancer cell lines, a 175-gene signature was defined and validated in patient-derived tumor xenograft models and ex vivo human acute myeloid leukemia (AML) cells. Second, an AML-specific 1,532-gene signature was defined by performing random forest analysis with cross-validation using gene expression profiles of 41 primary AML samples. The combination of TP53 mutation status with the two gene signatures provided the best positive predictive values (81% and 82%, compared with 62% for TP53 mutation status alone). In addition, the top-ranked 50 genes selected from the AML-specific 1,532-gene signature conserved high predictive performance, suggesting that a more feasible size of gene signature can be generated through this method for clinical implementation. Our model is being tested in ongoing clinical trials of MDM2 inhibitors.Significance: This study demonstrates that gene expression profiling combined with TP53 mutational status predicts antitumor effects of MDM2 inhibitors in vitro and in vivoCancer Res; 78(10); 2721-31. ©2018 AACR.

Practical Constant-Size Ring Signature

Bitcoin has gained its popularity for almost 10 years as a “secure and anonymous digital currency”. However, according to several recent researches, we know that it can only provide pseudonymity rather than real anonymity, and privacy has been one of the main concerns in the system similar to Bitcoin. Ring signature is a good method for those users who need better anonymity in cryptocurrency. It was first proposed by Rivest et al. based upon the discrete logarithm problem (DLP) assumption in 2006, which allows a user to sign a message anonymously on behalf of a group of users even without their coordination. The size of ring signature is one of the dominating parameters, and constant-size ring signature (where signature size is independent of the ring size) is much desirable. Otherwise, when the ring size is large, the resultant ring signature becomes unbearable for power limited devices or leads to heavy burden over the communication network. Though being extensively studied, currently there are only two approaches for constant-size ring signature. Achieving practical constant-size ring signature is a long-standing open problem since its introduction. In this work, we solve this open question. We present a new constant-size ring signature scheme based on bilinear pairing and accumulator, which is provably secure under the random oracle (RO) model. To the best of our knowledge, it stands for the most practical ring signature up to now.

An Identity‐Based Proxy Signature on NTRU Lattice

Proxy signature plays an important role in distributed systems, mobile agent applications, distributed shared object systems, global distribution networks and mobile communications etc., since it allows the original signer to delegate another proxy signer to sign the message instead of himself. However, the proxy signature schemes constructed on the number theory cannot resist quantum computers attack and depend on the public key infrastructure. To mitigate these problems, the alternative schemes are Identity-based proxy signature constructed on lattice. In this paper, an identity-based proxy signature scheme based on Number theorem research unit (NTRU) lattice is proposed and proven secure in the random oracle. Compared with the other existing identity-based proxy signature schemes, the proposed scheme outperforms them in terms of original signer's signature size and signing key size and proxy signer's signing key size.

Microarray‐based cancer diagnosis: repeated cross‐validation‐based ensemble feature selection

The influence of data resampling on ensemble methods, and repeated cross-validation (RCV)-based ensemble feature selection (FS) is proposed. To evaluate the proposed method, support vector machine and its extension and recursive feature elimination were used as the underlying classification and FS techniques, respectively. Experimental evaluation was performed using four microarray datasets. The results show that especially for extremely small signature sizes, increasing ensemble size increases both classification performance and the robustness of gene selection (stability) for both RCV and bootstrap (BS). However, for ensembles of the same size, RCV outperforms BS in terms of performance and especially stability. When compared to the top results obtained by two other studies in which BS is utilised, RCV performs similar or better in terms of area under the receiver operator curve and better in terms of stability.

CRYSTALS-Dilithium: A Lattice-Based Digital Signature Scheme

In this paper, we present the lattice-based signature scheme Dilithium, which is a component of the CRYSTALS (Cryptographic Suite for Algebraic Lattices) suite that was submitted to NIST’s call for post-quantum cryptographic standards. The design of the scheme avoids all uses of discrete Gaussian sampling and is easily implementable in constant-time. For the same security levels, our scheme has a public key that is 2.5X smaller than the previously most efficient lattice-based schemes that did not use Gaussians, while having essentially the same signature size. In addition to the new design, we significantly improve the running time of the main component of many lattice-based constructions – the number theoretic transform. Our AVX2-based implementation results in a speed-up of roughly a factor of 2 over the previously best algorithms that appear in the literature. The techniques for obtaining this speed-up also have applications to other lattice-based schemes.

Sectional MinHash for near-duplicate detection

MinHash is a widely-used method for efficiently estimating the amount of similarity between documents for Near-Duplicate Detection (NDD). However, it is based on the concept of set resemblance rather than near-duplication. In this study, Sectional MinHash (S-MinHash), specifically designed for the detection of near-duplicate documents, is proposed. The proposed method enhances the MinHash data structure with information about the location of the attributes in the document. The method provides an unbiased estimate of the Jaccard coefficient with a smaller variance as compared to the MinHash for same signature sizes. The experiment results showed that the Mean Squared Error (MSE) of the proposed method was around one eighth of the MSE of the MinHash. Also, document NDD with the proposed method resulted in more accuracy in compare to the MinHash and the recent method, the BitHash. The best-captured F-measure was 87.05%. Setting the number of sections s to 2 gave the best results for the tested dataset.

An Efficient Identity‐Based Proxy Blind Signature for Semioffline Services

Fog computing extends the cloud computing to the network edge and allows deploying a new type of semioffline services, which can provide real‐time transactions between two entities, while the central cloud server is offline and network edge devices are online. For an e‐payment system and e‐voting with such feature, proxy blind signature is a cornerstone to protect users’ privacy. However, the signature based on number theorem, such as hard mathematical problems on factoring problem, discrete logarithm problem, and bilinear pairings, cannot defeat quantum computers attack. Meanwhile, these schemes need to depend on complex public key infrastructure. Thus, we construct an identity‐based proxy blind signature scheme based on number theorem research unit lattice, which can defeat quantum computers attack and does not need to depend on public key infrastructure. The security of the proposed scheme is dependent on Ring‐Small Integer Solution problem over number theorem research unit lattice. The proposed scheme meets the properties of blind signature and proxy signature. Then we compare the proposed scheme with other existing proxy blind signature schemes; the result shows that the proposed scheme outperforms ZM scheme except in proxy signer’s signature size and can be more secure than TA scheme and MMHP scheme.

A New Post-Quantum Blind Signature From Lattice Assumptions

At present, several post-quantum cryptosystems have been proposed, and lattice-based cryptography is the main candidate. Especially in the direction of digital signatures, there are now many practical lattice-based signature schemes. However, there exist few lattice-based signatures with special property such as blind signature. Blind signature was introduced by Chaum for creating untraceable payment system. Then, it is widely used in e-cash and voting, especially in the revolutionary digital cash system based on blockchain. In our paper, we present a method to construct a post-quantum blind signature based on lattice assumptions, and we proved that any existential forger against the security of the resulting scheme can solve the ${\text {SIS}}_{q, n, m, \beta }$ problem for $\beta = \widetilde {O}(dn)$ . Our main technique is the rejection sampling theory. The expected number of times needed to output a blind signature is at most $e^{2}$ under aborting, and our new scheme has much smaller signature size than those of all the previously proposed blind signature schemes over lattices.

A New Efficient Certificateless Short Signature Scheme Using Bilinear Pairings

Recently, the idea of a certificateless short signature (CLSS) scheme has been proposed, as a way of supporting applications or devices in low-bandwidth communication environments, as well as certain devices with limited storage capacity. However, most CLSS schemes have adopted an inefficient and probabilistic hash function, called MapToPoint, making them hard for the computer system designer to implement efficiently. This paper develops a new efficient CLSS scheme using bilinear pairings. The proposed CLSS scheme has the lowest computational cost of signature generation and signature verification, compared to all of the other CLSS schemes. The signature length of our CLSS scheme is only one group element, which means that it is impossible for any CLSS scheme to have a lower signature size than ours. In addition, the MapToPoint operation is not used in our CLSS scheme, so the proposed scheme can be implemented more easily. A formal security analysis is presented, showing that the proposed scheme is secure against both super type I and super type II adversaries. Hence, the proposed scheme is suitable for both limited storage and limited computing capacity devices in low-bandwidth communication environments.

Asymptotically Efficient Lattice-Based Digital Signatures

We present a general framework that converts certain types of linear collision-resistant hash functions into one-time signatures. Our generic construction can be instantiated based on both general and ideal (e.g., cyclic) lattices, and the resulting signature schemes are provably secure based on the worst-case hardness of approximating the shortest vector (and other standard lattice problems) in the corresponding class of lattices to within a polynomial factor. When instantiated with ideal lattices, the time complexity of the signing and verification algorithms, as well as key and signature size, is almost linear (up to poly-logarithmic factors) in the dimension n of the underlying lattice. Since no sub-exponential (in n) time algorithm is known to solve lattice problems in the worst case, even when restricted to ideal lattices, our construction gives a digital signature scheme with an essentially optimal performance/security trade-off.

Energy aware and fast authentication scheme using identity based encryption in wireless sensor networks

Wireless sensor networks described as an emerging new technology with a very promising future. Advances made in wireless sensor networks (WSNs) are the merging of advanced electronic and wireless technologies. Due to the popularity gained by the wireless environment, Security is the main concern. Node authentication without compromising lifespan of the networks is practically a daunting task. This research work introduces a new model, IBE-ECC that administers the energy of sensor nodes with faster authentication process. Signature verification model is deployed to achieve faster authentication process. Nevertheless, the public key-based strategies eliminate the security process but their verification process takes larger time. Therefore, authentication speed is a major constraint of our research endeavor. The proposed scheme is design to achieve high security and fast authentication with energy efficiency. It uses identity-based encryption on elliptic curve cryptography and a user authentication with an energy efficient key management. Further, to improve the speed of the authentication, it reduces the signature size so that it would accelerate signature verification faster. Hence, the proposed scheme will provide a secure key management, energy efficiency, fast authentication and additionally, computation overhead and communication costs are minimized. Finally, the experimental result demonstrates that the proposed strategy obtains 4797 ms higher execution efficiency and 45. 53% lower computation costs than existing schemes.

P.4.e.004 - MicroRNA signature associated with enhanced vulnerability to develop psychiatric disorders: dissecting the mechanisms by using an in vitro model

We construct new leakage-resilient signature schemes. Our schemes remain unforgeable against an adversary leaking arbitrary (yet bounded) information on the entire state of the signer (sometimes known as fully leakage resilience), including the random coin tosses of the signing algorithm.The main feature of our constructions is that they offer a graceful degradation of security in situations where standard existential unforgeability is impossible. This property was recently put forward by Nielsen, Venturi, and Zottarel (PKC 2014) [19] to deal with settings in which the secret key is much larger than the size of a signature. One remarkable such case is the so-called Bounded-Retrieval Model (BRM), where one intentionally inflates the size of the secret key while keeping constant the signature size and the computational complexity of the scheme.Our main constructions have leakage rate 1−o(1), and are proven secure in the standard model. We additionally give a construction in the BRM, relying on a random oracle. All of our schemes are described in terms of generic building blocks, but also admit efficient instantiations under fairly standard number-theoretic assumptions. Finally, we explain how to extend some of our schemes to the setting of noisy leakage, where the only restriction on the leakage functions is that the output does not decrease the min-entropy of the secret key by too much.

Narcissism is a bad sign: CEO signature size, investment, and performance

Using the size of CEO signatures in SEC filings to measure individual narcissism, we find that CEO narcissism is associated with several negative firm outcomes. We first validate signature size as a measure of narcissism but not overconfidence using two laboratory studies, and also find that our measure is correlated with employee perceptions of CEO narcissism used in prior research. We then use CEO signatures to study the relation between CEO narcissism and the firm’s investment policies and performance. CEO narcissism is associated with overinvestment, particularly in R&D and M&A expenditures (but not in capital expenditures). Firms led by narcissistic CEOs experience lower financial productivity in the form of profitability and operating cash flows. Despite this negative performance, narcissistic CEOs enjoy higher absolute and relative compensation. Our results are robust to several alternative specifications, including controlling for a popular options-based overconfidence measure used in prior research.

Multicohort analysis reveals baseline transcriptional predictors of influenza vaccination responses.

Annual influenza vaccinations are currently recommended for all individuals 6 months and older. Antibodies induced by vaccination are an important mechanism of protection against infection. Despite the overall public health success of influenza vaccination, many individuals fail to induce a substantial antibody response. Systems-level immune profiling studies have discerned associations between transcriptional and cell subset signatures with the success of antibody responses. However, existing signatures have relied on small cohorts and have not been validated in large independent studies. We leveraged multiple influenza vaccination cohorts spanning distinct geographical locations and seasons from the Human Immunology Project Consortium (HIPC) and the Center for Human Immunology (CHI) to identify baseline (i.e., before vaccination) predictive transcriptional signatures of influenza vaccination responses. Our multicohort analysis of HIPC data identified nine genes (RAB24, GRB2, DPP3, ACTB, MVP, DPP7, ARPC4, PLEKHB2, and ARRB1) and three gene modules that were significantly associated with the magnitude of the antibody response, and these associations were validated in the independent CHI cohort. These signatures were specific to young individuals, suggesting that distinct mechanisms underlie the lower vaccine response in older individuals. We found an inverse correlation between the effect size of signatures in young and older individuals. Although the presence of an inflammatory gene signature, for example, was associated with better antibody responses in young individuals, it was associated with worse responses in older individuals. These results point to the prospect of predicting antibody responses before vaccination and provide insights into the biological mechanisms underlying successful vaccination responses.

CFO Narcissism and Financial Reporting Quality

ABSTRACTWe investigate the effect of CFO narcissism, as measured by signature size, on financial reporting quality. Experimentally, we validate that narcissism predicts misreporting behavior, and that signature size predicts misreporting through its association with narcissism. Empirically, we examine notarized CFO signatures and find CFO narcissism is associated with more earnings management, less timely loss recognition, weaker internal control quality, and a higher probability of restatements. The results are consistent for within‐firm comparisons focusing on CFO changes and are robust to controlling for CFO overconfidence and CEO narcissism. The results highlight the importance of CFO characteristics in the domain of financial reporting decisions.

Lattice-based group signature with verifier-local revocation

Among several post quantum primitives proposed in the past few decades, lattice-based cryptography is considered as the most promising one, due to its underlying rich combinatorial structure, and the worst-case to average-case reductions. The first lattice-based group signature scheme with verifier-local revocation (VLR) is treated as the first quantum-resistant scheme supported member revocation, and was put forward by Langlois et al. This VLR group signature (VLR-GS) has group public key size of O(nm log N log q), and a signature size of O(tm logN log q log β). Nguyen et al. constructed a simple efficient group signature from lattice, with significant advantages in bit-size of both the group public key and the signature. Based on their work, we present a VLR-GS scheme with group public key size of O(nm log q) and signature size of O(tm log q). Our group signature has notable advantages: support of membership revocation, and short in both the public key size and the signature size.

Efficient message recovery proxy blind signature scheme from pairings

AbstractThe recent applications of communication technology like e‐bookings, e‐shopping, e‐cash, etc. have inspired the need of delegation of signing capacity along with anonymity. A proxy blind signature scheme is a method of such delegation along with anonymity. In these signature schemes, a user can get a signature on a document of her/his choice from a proxy signer (who is signing the document on behalf of an original signer with delegated signing power) without revealing its contents. These signature schemes are mostly used by low bandwidth systems and thus small messages are signed. In this article, we introduce a proxy blind signature scheme with message recovery to shorten the message signature size. Through comparison with existing efficient proxy blind signature schemes, we show that the proposed scheme is the shortest in size and more efficient in computation cost.

Automated detection and enumeration of marine wildlife using unmanned aircraft systems (UAS) and thermal imagery

Estimating animal populations is critical for wildlife management. Aerial surveys are used for generating population estimates, but can be hampered by cost, logistical complexity, and human risk. Additionally, human counts of organisms in aerial imagery can be tedious and subjective. Automated approaches show promise, but can be constrained by long setup times and difficulty discriminating animals in aggregations. We combine unmanned aircraft systems (UAS), thermal imagery and computer vision to improve traditional wildlife survey methods. During spring 2015, we flew fixed-wing UAS equipped with thermal sensors, imaging two grey seal (Halichoerus grypus) breeding colonies in eastern Canada. Human analysts counted and classified individual seals in imagery manually. Concurrently, an automated classification and detection algorithm discriminated seals based upon temperature, size, and shape of thermal signatures. Automated counts were within 95–98% of human estimates; at Saddle Island, the model estimated 894 seals compared to analyst counts of 913, and at Hay Island estimated 2188 seals compared to analysts’ 2311. The algorithm improves upon shortcomings of computer vision by effectively recognizing seals in aggregations while keeping model setup time minimal. Our study illustrates how UAS, thermal imagery, and automated detection can be combined to efficiently collect population data critical to wildlife management.