The Experts below are selected from a list of 4464 Experts worldwide ranked by ideXlab platform
Ronglin Hao - One of the best experts on this subject based on the ideXlab platform.
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cryptanalysis of reduced round Whirlwind
Australasian Conference on Information Security and Privacy, 2015Co-Authors: Ronglin HaoAbstract:The Whirlwind hash function, which outputs a 512-bit digest, was designed by Barreto \(et\ al.\) and published by Design, Codes and Cryptography in 2010. In this paper, we provide a thorough cryptanalysis on Whirlwind. Firstly, we focus on security properties at the hash function level by presenting (second) preimage, collision and distinguishing attacks on reduced-round Whirlwind. In order to launch the preimage attack, we have to slightly tweak the original Meet-in-the-Middle preimage attack framework on AES-like compression functions by partially fixing the values of the state. Based on this slightly tweaked framework, we are able to construct several new and interesting preimage attacks on reduced-round Whirlpool and AES hashing modes as well. Secondly, we investigate security properties of the reduced-round components of Whirlwind, including semi-free-start and free-start (near) collision attacks on the compression function, and a limited-birthday distinguisher on the inner permutation. As far as we know, our results are currently the best cryptanalysis on Whirlwind.
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ACISP - Cryptanalysis of Reduced-Round Whirlwind
Information Security and Privacy, 2015Co-Authors: Ronglin HaoAbstract:The Whirlwind hash function, which outputs a 512-bit digest, was designed by Barreto \(et\ al.\) and published by Design, Codes and Cryptography in 2010. In this paper, we provide a thorough cryptanalysis on Whirlwind. Firstly, we focus on security properties at the hash function level by presenting (second) preimage, collision and distinguishing attacks on reduced-round Whirlwind. In order to launch the preimage attack, we have to slightly tweak the original Meet-in-the-Middle preimage attack framework on AES-like compression functions by partially fixing the values of the state. Based on this slightly tweaked framework, we are able to construct several new and interesting preimage attacks on reduced-round Whirlpool and AES hashing modes as well. Secondly, we investigate security properties of the reduced-round components of Whirlwind, including semi-free-start and free-start (near) collision attacks on the compression function, and a limited-birthday distinguisher on the inner permutation. As far as we know, our results are currently the best cryptanalysis on Whirlwind.
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Cryptanalysis of Reduced-Round Whirlwind (Full Version) ?
2015Co-Authors: Ronglin HaoAbstract:The Whirlwind hash function, which outputs a 512-bit digest, was designed by Barreto et al: and published by Design, Codes and Cryptography in 2010. In this paper, we provide a thorough cryptanalysis on Whirlwind. Firstly, we focus on security properties at the hash function level by presenting (second) preimage, collision and distinguishing attacks on reduced-round Whirlwind. In order to launch the preimage attack, we have to slightly tweak the original Meet-in-the-Middle preimage attack framework on AES-like compression functions by partially xing the values of the state. Based on this slightly tweaked framework, we are able to construct several new and interesting preimage attacks on reduced-round Whirlpool and AES hashing modes as well. Secondly, we investigate security properties of the reduced-round components of Whirlwind, including semi-free-start and free-start (near) collision attacks on the compression function, and a limited-birthday distinguisher on the inner permutation. As far as we know, our results are currently the best cryptanalysis on Whirlwind.
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cryptanalysis of reduced round Whirlwind full version
IACR Cryptol. ePrint Arch., 2015Co-Authors: Ronglin HaoAbstract:The Whirlwind hash function, which outputs a 512-bit digest, was designed by Barreto et al: and published by Design, Codes and Cryptography in 2010. In this paper, we provide a thorough cryptanalysis on Whirlwind. Firstly, we focus on security properties at the hash function level by presenting (second) preimage, collision and distinguishing attacks on reduced-round Whirlwind. In order to launch the preimage attack, we have to slightly tweak the original Meet-in-the-Middle preimage attack framework on AES-like compression functions by partially xing the values of the state. Based on this slightly tweaked framework, we are able to construct several new and interesting preimage attacks on reduced-round Whirlpool and AES hashing modes as well. Secondly, we investigate security properties of the reduced-round components of Whirlwind, including semi-free-start and free-start (near) collision attacks on the compression function, and a limited-birthday distinguisher on the inner permutation. As far as we know, our results are currently the best cryptanalysis on Whirlwind.
Xiuqing Hu - One of the best experts on this subject based on the ideXlab platform.
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5-axis CNC Whirlwind Milling Model for Complex Freeform Surfaces
2006 International Conference on Mechatronics and Automation, 2006Co-Authors: Xianzhong Yi, Shengli Fu, Jingkun Zhao, Xiuqing HuAbstract:Whirlwind milling model is a new milling technique proposed in this paper based on 5-axis CNC horizontal bed-type milling machines. The machining strategy of this model is to make a real-time adjustment of cutter orientation of Whirlwind milling tool so as to create a close approaching envelopment to the surface being machined with the milling-tool rotational surface. Then, a full approach between these two surfaces can ensure maximizing the material removal on the machined surface at point of contact and improve the machining quality. A Whirlwind milling tool with standard-sized circular edge cutters is introduced to side-mill complex freeform surfaces. The fundamentals, kinematics relationship, cutter location equations and tool path generation about this new milling model are analyzed, and some real application is presented
Qiang Liu - One of the best experts on this subject based on the ideXlab platform.
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Tool path generation of 5-axis CNC Whirlwind milling model for freeform surfaces
IEEE International Conference Mechatronics and Automation 2005, 1Co-Authors: Qiang LiuAbstract:The normal curvature approach model is a new method proposed for generating interference-free tool paths in machining the freeform surfaces on five-axis CNC machines, and a specialized Whirlwind milling tool is also introduced in the paper. The crux of this new tool path model is to optimize the CL-data of Whirlwind milling tool so as to closely approach to the surface being machined. So, this new milling method evidently raises the material removal rate at the point of contact. The stepforwards and step-overs of NC tool paths are determined by the accuracy of the manufactured surfaces. Under the same scallop height and dimensional precision, this method can shorten the number of tool passes and cut down the manufacturing cost.
Xianzhong Yi - One of the best experts on this subject based on the ideXlab platform.
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5-axis CNC Whirlwind Milling Method on Helical Surfaces of PDM's Rotors
2010 International Conference on Measuring Technology and Mechatronics Automation, 2010Co-Authors: Xianzhong Yi, Tiegang Xu, Zesheng Yan, Deli GaoAbstract:The positive displacement motor (PDM) is a very important downhole motor in petroleum exploration and production. The key element in PDMs is the rotor-stator coupling which converts hydraulic potential of high-pressure fluid medium into mechanical energy. Normally both the rotor and the stator are constituted of cylindrical helix surfaces. The PDM's characteristics directly rely on the machining quality of rotor-stator coupling. 3-axis and 4-axis NC milling machines are usually used to machine the rotor helix surface or helix surface of stator mandrel, which is an injecting molding part utilized to shape the internal cavity of rubber stator. The current CNC milling technology for manufacturing large and complex spiral curved surfaces still retains the drawbacks such as consuming time of long duration, over-tolerance and gouging scores. A new 5-axis CNC machining scheme with the Whirlwind milling method is proposed based on 5-axis CNC rotary-table horizontal milling machine specialized. The important strategy of the Whirlwind milling technique is to optimize the directions of principal curvatures of the surface being machined with those of the rotational surface of milling cutter to generate a perfect fit. So, it can avoid the above-mentioned shortcomings and enhance the productivity. Some analytical characteristics of helical surfaces are discussed. The fundamental mathematical equations on Whirlwind milling technique and its implementation are introduced.
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5-axis CNC Whirlwind Milling Model for Complex Freeform Surfaces
2006 International Conference on Mechatronics and Automation, 2006Co-Authors: Xianzhong Yi, Shengli Fu, Jingkun Zhao, Xiuqing HuAbstract:Whirlwind milling model is a new milling technique proposed in this paper based on 5-axis CNC horizontal bed-type milling machines. The machining strategy of this model is to make a real-time adjustment of cutter orientation of Whirlwind milling tool so as to create a close approaching envelopment to the surface being machined with the milling-tool rotational surface. Then, a full approach between these two surfaces can ensure maximizing the material removal on the machined surface at point of contact and improve the machining quality. A Whirlwind milling tool with standard-sized circular edge cutters is introduced to side-mill complex freeform surfaces. The fundamentals, kinematics relationship, cutter location equations and tool path generation about this new milling model are analyzed, and some real application is presented
Tyson L. Hedrick - One of the best experts on this subject based on the ideXlab platform.
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Hawkmoth flight performance in tornado-like Whirlwind vortices.
Bioinspiration & biomimetics, 2014Co-Authors: Victor Manuel Ortega-jimenez, Rajat Mittal, Tyson L. HedrickAbstract:Vertical vortex systems such as tornadoes dramatically affect the flight control and stability of aircraft. However, the control implications of smaller scale vertically oriented vortex systems for small fliers such as animals or micro-air vehicles are unknown. Here we examined the flapping kinematics and body dynamics of hawkmoths performing hovering flights (controls) and maintaining position in three different Whirlwind intensities with transverse horizontal velocities of 0.7, 0.9 and 1.2 m s?1, respectively, generated in a vortex chamber. The average and standard deviation of yaw and pitch were respectively increased and reduced in comparison with hovering flights. Average roll orientation was unchanged in Whirlwind flights but was more variable from wingbeat to wingbeat than in hovering. Flapping frequency remained unchanged. Wingbeat amplitude was lower and the average stroke plane angle was higher. Asymmetry was found in the angle of attack between right and left wings during both downstroke and upstroke at medium and high vortex intensities. Thus, hawkmoth flight control in tornado-like vortices is achieved by a suite of asymmetric and symmetric changes to wingbeat amplitude, stroke plane angle and principally angle of attack.
