Research on Key Technical Indexes of Coastal Reclamation Planning and Design

Large-scale coastal reclamation has become a significant land use issue worldwide for urban construction and economic development. The reclamation of coastal wetlands brings substantial economic benefits, however, the structure and function of coastal ecosystem are affected by drivers of human-caused landscape change. This research takes Hangzhou Bay and Zhoushan Islands as the case study to investigate the correlation between the coastal geomorphic complexity and the tidal range reduction rate, and to explore the control technical indexes of the design in reclamation area by a multidisciplinary approach that integrates the basic theories and quantitative methods of fractal geometry with the hydrodynamic mechanism of ocean dynamics. The results show that the coastal tidal range reduction rate is closely related to the coastline fractal dimension and patch shape index (D, S), and reveals the influence of the complexity of the coastal landscape on the tidal energy loss. In addition, based on model predictions, it can be found that the large-scale reclamation in Zhoushan will cause a serious decline in the complexity of the coastal landscape and the reduction of tidal energy, which is extremely detrimental to coastal disaster prevention. In the end, the scientific design theory and quantitative control indexes of reclamation are put forward to provide theoretical basis and design reference for future coastal reclamation and disaster prevention.

New Bleichenbacher Records: Fault Attacks on qDSA Signatures

In this paper, we optimize Bleichenbacher’s statistical attack technique against (EC)DSA and other Schnorr-like signature schemes with biased or partially exposed nonces. Previous approaches to Bleichenbacher’s attack suffered from very large memory consumption during the so-called “range reduction” phase. Using a carefully analyzed and highly parallelizable approach to this range reduction based on the Schroeppel–Shamir algorithm for knapsacks, we manage to overcome the memory barrier of previous work while maintaining a practical level of efficiency in terms of time complexity.As a separate contribution, we present new fault attacks against the qDSA signature scheme of Renes and Smith (ASIACRYPT 2017) when instantiated over the Curve25519 Montgomery curve, and we validate some of them on the AVR microcontroller implementation of qDSA using actual fault experiments on the ChipWhisperer-Lite evaluation board. These fault attacks enable an adversary to generate signatures with 2 or 3 bits of the nonces known.Combining our two contributions, we are able to achieve a full secret key recovery on qDSA by applying our version of Bleichenbacher’s attack to these faulty signatures. Using a hybrid parallelization model relying on both shared and distributed memory, we achieve a very efficient implementation of our highly scalable range reduction algorithm. This allows us to complete Bleichenbacher’s attack in the 252-bit prime order subgroup of Curve25519 within a reasonable time frame and using relatively modest computational resources both for 3-bit nonce exposure and for the much harder case of 2-bit nonce exposure. Both of these computations, and particularly the latter, set new records in the implementation of Bleichenbacher’s attack.