低轮FOX分组密码的碰撞-积分攻击

FOX是最近推出的系列分组密码，它的设计思想基于可证安全的研究结果，且在各种平台上的性能优良．本文利用碰撞攻击和积分攻击相结合的技术分析FOX的安全性，结果显示碰撞-积分攻击比积分攻击有效，攻击对4轮FOX64的计算复杂度是2^45.4，对5轮FOX64的计算复杂度是2^109.4，对6轮FOX64的计算复杂度是2^173.4，对7轮FOX64的计算复杂度是2^237.4，且攻击所需数据量均为2^9；也就是说4轮FOX64／64、5轮FOX64／128、6轮FOX64／192和7轮FOX64／256对本文攻击是不免疫的．

关于Noekeon分组密码

Noekeon是NESSIE公布的17个候选算法之一,讨论了Noekeon各个模块的密码特性及它们在整个密码中的作用,从中体会Noekeon的设计技巧.

CO2置换开采天然气水合物研究进展

介绍了近年来CO2置换开采天然气水合物技术的研究进展；论述了CO2与天然气水合物中CH4置换反应在热力学上的可能性；认为正确理解置换反应机理、探索新的反应技术并提高反应速率是置换开采技术走向产业化的关键。

Replacement of methane from quartz sand-bearing hydrate with carbon dioxide-in-water emulsion

The replacement of CH4 from its hydrate in quartz sand with 90:10, 70:30, and 50:50 (W-CO2:W-H2O) carbon dioxide-in-water (C/W) emulsions and liquid CO2 has been performed in a cell with size of empty set 36 x 200 mm. The above emulsions were formed in a new emulsifier, in which the temperature and pressure were 285.2 K and 30 MPa, respectively, and the emulsions were stable for 7-12 h. The results of replacing showed that 13.1-27.1%, 14.1-25.5%, and 14.6-24.3% of CH4 had been displaced from its hydrate with the above emulsions after 24-96 It of replacement, corresponding to about 1.5 times the CH4 replaced with high-pressure liquid CO2. The results also showed that the replacement rate of CH4 with the above emulsions and liquid CO2 decreased from 0.543, 0.587, 0.608, and 0.348 1/h to 0.083, 0.077, 0.069, and 0.063 1/h with the replacement time increased from 24 to 96 h. It has been indicated by this study that the use of CO2 emulsions is advantageous compared to the use of liquid CO2 in replacing CH4 from its hydrate.

a new client-to-client password-authenticated key agreement protocol

Natl Univ Defen Technol, China & Nanyang Technol Univ, NUDT

In Situ Scanning Tunneling Microscopy on the Dynamic Process of the Replacement of Coronene on Au (111) by 6-Mercapto-1-Hexanol

The replacement of coronene monolayer on Au (111) by 6-mercapto-1-hexanol (MHO) was studied by in situ scanning tunneling microscopy (STM) in solutions. It was found that the rate of replacement depends strongly on the concentration of MHO. The replacement finished within a second at a higher concentration of MHO. At a lower concentration, the slow replacement could be followed by in situ STM. The replacement occurred initially near the elbow position of reconstructed Au (111) with the formation of pits in a single or several missing molecules. With the proceeding of replacement, these small pits expanded, and the surrounding coronene molecules were gradually substituted by MHO, which developed into ordered domains within a spatial confined environment. Meanwhile, the reconstruction of Au (111) was lifted. The replacement expanded fast along the reconstruction lines in the domain. For the fast replacement, a (root 3 x root 3) R30 degrees adlattice was observed, while a c(4 x 2) superlattice was observed for the slow replacement.