PRICING OPTIONS UNDER STOCHASTIC INTEREST RATE AND THE FRASCA–FARINA PROCESS: A SIMPLE, EXPLICIT FORMULA

Assuming a stochastic interest rate, we introduce a simple formula for pricing European options. In doing so, we provide a complete closed-form formula that does not require any numerical/computational methods. Furthermore, the model and formula are far simpler than the previous models/formulas. Our formula is as simple as the classical Black–Scholes pricing formula. Moreover, it removes the theoretical limitation of the original Black–Scholes model without any added practical complexity.

Improved Preimage Attacks on 4-Round Keccak-224/256

This paper provides an improved preimage attack method on standard 4-round Keccak-224/256. The method is based on the work pioneered by Li and Sun, who design a linear structure of 2-round Keccak-224/256 with 194 degrees of freedom left. By partially linearizing 17 output bits through the last 2 rounds, they finally reach a complexity of 2207/2239 for searching a 4-round preimage. Yet under their strategy, those 17 bits are regarded as independent bits and the linearization costs a great amount of freedom. Inspired by their thoughts, we improve the partial linearization method where multiple output bits can reuse some common degrees of freedom. As a result, the complexity of preimage attack on 4-round Keccak-224/256 can be decreased to 2192/2218, which are both the best known theoretical preimage cryptanalysis so far. To support the theoretical analysis, we apply our strategy to a 64-bit partial preimage attack within practical complexity. It is remarkable that this partial linearization method can be directly applied if a better linear structure with more freedom left is proposed.

Mediality: the cultural-symbolic sphere of social practice

At least since the practical complexity of media landscapes is growing, the theoretical complexity of media communication has to be widened (horizon and frame) and deepened (focus) — especially when fulfilling the mission and the quality of science: generating complexity on a level of logical theory towards a subject that is not an object by itself but a culturally programmed metaphor of description: communication, culture, society etc. The complexity of communication, media or society is not a character of those constructs themselves but a complexity of thinking, in practice hopefully reduced, in theory hopefully produced. Facing communication (more) as a cultural performance of humanness and of social practice and facing media (more hermeneutically than technically) demands to conceptualize those constructs as models of knowledge, as culturally programs in search of mindful meaning and meaningful relevance of social /societal life. Therefore, there is need of a shifting paradigm from functional, objectivist concepts to hermeneutically open concepts — not only, but also to generate a wider frame of analysis and interpretation of social and cultural change referred through the mediality character of communication and society. So called social media are not new media but show the possibility as well the challenge and chance of change of media orders. Of course, that demands other (new) competence concepts of social practice.

Strongly Budget Balanced Auctions for Multi-Sided Markets

In two-sided markets, Myerson and Satterthwaite's impossibility theorem states that one can not maximize the gain-from-trade while also satisfying truthfulness, individual-rationality and no deficit. Attempts have been made to circumvent Myerson and Satterthwaite's result by attaining approximately-maximum gain-from-trade: the double-sided auctions of McAfee (1992) is truthful and has no deficit, and the one by Segal-Halevi et al. (2016) additionally has no surplus — it is strongly-budget-balanced. They consider two categories of agents — buyers and sellers, where each trade set is composed of a single buyer and a single seller.The practical complexity of applications such as supply chain require one to look beyond two-sided markets. Common requirements are for: buyers trading with multiple sellers of different or identical items, buyers trading with sellers through transporters and mediators, and sellers trading with multiple buyers. We attempt to address these settings.We generalize Segal-Halevi et al. (2016)'s strongly-budget-balanced double-sided auction setting to a multilateral market where each trade set is composed of any number of agent categories. Our generalization refines the notion of competition in multi-sided auctions by introducing the concepts of external competition and trade reduction. We also show an obviously-truthful implementation of our auction using multiple ascending prices.Full version, including omitted proofs and simulation experiments, is available at https://arxiv.org/abs/1911.08094.

Signal Detection Based on Parallel Group Detection Algorithm for High-Load Massive MIMO Systems

In this paper, a parallel group detection (PGD) algorithm is proposed in order to address the degradation in the bit error rate (BER) performance of linear detectors when they are used in high-load massive MIMO systems. The algorithm is constructed by converting the equivalent extended massive MIMO system into two subsystems, which can be simultaneously detected by the classical detection procedures. Then, using the PGD and the classical ZF as well as the QR-decomposition- (QRD-) based detectors, we proposed two new detectors, called ZF-based PGD (ZF-PGD) and QRD-based PGD (QRD-PGD). The PGD is further combined with the sorted longest basis (SLB) algorithm to make the signal recovery more accurate, thereby resulting in two new detectors, namely, the ZF-PGD-SLB and the QRD-PGD-SLB. Various complexity evaluations and simulations prove that the proposed detectors can significantly improve the BER performance compared to their classical linear and QRD counterparts with the practical complexity levels. Hence, our proposed detectors can be used as efficient means of estimating the transmitted signals in high-load massive MIMO systems.

Random Fault Attacks on a Class of Stream Ciphers

In this paper, we show that stream ciphers with a particular form of ciphertext output function are vulnerable to differential fault attacks using random faults. The CAESAR competition candidates Tiaoxin-346 and AEGIS-128L both fall into this category, and we show that our attack can be used to recover the secret key of Tiaoxin-346 and the entire state of AEGIS-128L with practical complexity. In the case of AEGIS-128L, the attack can be applied in a ciphertext-only scenario. Our attacks are more practical than previous fault attacks on these ciphers, which assumed bit-flipping faults. Although we also consider other ways of mitigating our attacks, we recommend that cipher designers avoid the form of ciphertext output function that we have identified.

New Yoyo Tricks with AES-based Permutations

In Asiacrypt 2017, Rønjom et al. reported some interesting generic properties of SPNs, leading to what they call the Yoyo trick, and applied it to find the most efficient distinguishers on AES. In this work, we explore the Yoyo idea in distinguishing public permutations for the first time. We introduce the notion of nested zero difference pattern which extends the Yoyo idea and helps to compose it using improbable and impossible differential strategies to penetrate higher number of rounds. We devise a novel inside-out application of Yoyo which enables us to start the Yoyo game from an internal round. As an application, we investigate the AES-based public permutation AESQ used inside the authenticated cipher PAEQ. We achieve the first deterministic distinguisher of AESQ up to 8 rounds and the first 9-round distinguisher of AESQ that start from the first round with a practical complexity of around 226. We manage to augment Yoyo with improbable and impossible differentials leading to distinguishers on 9, 10, 12 rounds with complexities of about 22, 228, 2126 respectively. Further, with impossible differentials and a bi-directional Yoyo strategy, we obtain a 16-round impossible differential distinguisher with a complexity of 2126. Our results outperform all previous records on AESQ by a substantial margin. As another application, we apply the proposed strategies on AES in the known-key setting leading to one of the best 8-round known-key distinguisher with a complexity of 230. Finally, this work amplifies the scope of the Yoyo technique as a generic cryptanalysis tool.

Theories and Practices of Sustainable Development in Africa

Sustainable development (SD) involves economic growth with non-declining inter-generational benefit by maintaining environmental balance overtime. However, the conceptual and practical complexity of traditional SD has challenged its implementation. Consequently, this chapter provides a modified approach to SD called Institutionalized Sustainable Development (ISD) model, which augments the institutional governance into the three pillars of sustainable development: social, economic and environmental aspects. It argues that SD can be achieved when capable institutions are established that can optimize resource use; integrate economic development, environment and social inclusion. The Sustainable development practice of Africa has been assessed and lessons are drawn for future development ends. The resource use, task, and goal prioritization are the main motivators of developing these models. Its application requires development of indigenous knowledge and local capacity, planned investment, good governance, research and innovation directed towards realization of inclusive sustainable development in Africa.