On the Powerline System

The powerline system introduced by H.W. Lenstra in 1991 is a modification of the Chor-Rivest system, which was based upon a theorem by Bose and Chowla. The powerline system was proved by his author to be at least as secure as the Chor-Rivest system and has the main advantage of a greater freedom in choosing the system parameters. It does not rely on a hard problem from number theory. However its information rate is low. An improved powerline system called fractional powerline is introduced here. It has a better information rate and as a consequence, the brute-force attack already considered by Chor and Rivest which is adapted to this new system, is much more laborious. The system is still improved by introducing other irreducible polynomials. Improving the powerline system leads to results in arithmetic which are an extention and a variant to the theorem of Bose and Chowla. The main practical implication is to be able to transmit a 135 bit key over an channel together with an interactive signature by conveying only 208 × 2 binary digits. Received: July 24, 1997; revised version: January 26, 1998     

PDM系统间的安全交互模型

现有的用户名/密码等访问控制机制在交互时存在着很大的安全缺陷.为了更有效地满足企业产品数据管理(PDM)系统安全交互的需求,在现有企业PDM系统的通用安全管理模型的基础上,提出并设计实现了基于公钥证书的属性证书模型-AA代理模型.新模型依据TTP(可信第三方)的结构来传递企业间的信任关系,增强了企业协作的自动化,减少了交互的成本.它不仅实现了可靠的身份鉴定和安全的数据传输,同时也实现了灵活的访问控制和安全审计功能,有效地解决了企业信息交互的问题,可用于汽车、电子、机械等制造行业.     

The Candida albicans PKC1 gene encodes a protein kinase C homolog necessary for cellular integrity but not dimorphism

Using a DNA fragment derived from the Saccharomyces cerevisiae protein kinase C gene (PKC1) as a probe to screen an ordered array library of genomic DNA from the dimorphic pathogenic fungus Candida albicans, the C. albicans PKC1 gene (CaPKC1) was isolated. The CaPKC1 gene is predicted to encode a protein of 1079 amino acids with 51% sequence identity over the entire length with the S. cerevisiae Pkc1 protein and is capable of functionally complementing the growth defects of a S. cerevisiae pkc1Δ mutant strain on hypo-osmotic medium. Deletion of both endogenous copies of the CaPKC1 gene in diploid C. albicans cells resulted in an osmotically remedial cell lysis defect of both the budding and the hyphal growth form and morphologically aberrant cells of the budding form. Despite these abnormalities, the transition between the two growth forms of C. albicans occurred normally in pkc1/pkc1 double disruptants. Capkc1p was modified at its C-terminus with two repeats of the Staphylococcus aureus protein A IgG-binding fragment (ZZ-sequence tag) and partially purified by chromatography on DEAE–Sepharose and IgG–Sepharose. In vitro, Capkc1p preferably phosphorylated the S. cerevisiae Pkc1p pseudosubstrate peptide and myelin basic protein, but not histones, protamine or dephosphorylated casein, and failed to respond to cofactors known to activate several mammalian PKC isozymes.     

Kinase Signaling in Apoptosis Induced by Saturated Fatty Acids in Pancreatic β-Cells

Pancreatic β-cell failure and death is considered to be one of the main factors responsible for type 2 diabetes. It is caused by, in addition to hyperglycemia, chronic exposure to increased concentrations of fatty acids, mainly saturated fatty acids. Molecular mechanisms of apoptosis induction by saturated fatty acids in β-cells are not completely clear. It has been proposed that kinase signaling could be involved, particularly, c-Jun N-terminal kinase (JNK), protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK), and Akt kinases and their pathways. In this review, we discuss these kinases and their signaling pathways with respect to their possible role in apoptosis induction by saturated fatty acids in pancreatic β-cells.     

基于PKI/PMI的IP宽带城域网安全应用解决方案

随着网络技术的发展演变，IP宽带城域网已成为宽带网络的发展方向，各种信息化应用都将基于IP技术。本在分析目前IP宽带城域网在安全应用与管理方面存在问题的基础上，首先简单介绍了PKI／PMI，然后阐述了如何应用基于PKI／PMI的智能化信任与授权技术来建立IP宽带城域网的可信任环境，如何利用数字证书来实现基于证书和端口的IP宽带城域网安全应用与管理模式，该模式类似于PSTN中基于号线的应用与管理模式，从而构建一个“可控制、可管理、可经营”的电信级IP宽带城域网，为各种信息化应用提供一个安全可信的基础电信网络平台。     

A new scheme based on the MI scheme and its analysis

This article aims at designing a new Multivariate Quadratic (MQ) public-key scheme to avoid the linearization attack and differential attack against the Matsumoto-Imai (MI) scheme. Based on the original scheme, our new scheme, named the Multi-layer MI (MMI) scheme, has a structure of multi-layer central map. Firstly, this article introduces the MI scheme and describes linearization attack and differential attack; then prescribes the designation of MMI in detail, and proves that MMI can resist both linearization attack and differential attack. Besides, this article also proves that MMI can resist recent eXtended Linearization (XL)-like methods. In the end, this article concludes that MMI also maintains the efficiency of MI.     

Involvement of Calcium-Mediated Reactive Oxygen Species in Inductive GRP78 Expression by Geldanamycin in 9L Rat Brain Tumor Cells

Treatment with geldanamycin (GA) leads to an increase in [Ca²⁺]_c and the production of reactive oxygen species (ROS) in rat brain tumor 9L RBT cells. GA-exerted calcium signaling was blocked by BAPTA/AM and EGTA. The effect of GA on [Ca²⁺]_c was significantly reduced in the presence of thapsigargin (TG) and ruthenium red (RR). GA-induced GRP78 expression is significantly decreased in the presence of BAPTA/AM, EGTA and RR, suggesting that the calcium influx from the extracellular space and intracellular calcium store oscillations are contributed to by the calcium mobilization and GRP78 expression induced by GA. The induced GRP78 expression is sensitive to added {"type":"entrez-nucleotide","attrs":{"text":"U73122","term_id":"4098075","term_text":"U73122"}}U73122 and Ro-31-8425, pinpointing the involvement of phospholipase C (PLC) and protein kinase C (PKC) in GA-induced endoplasmic reticulum (ER) stress. The antioxidants N-acetylcysteine (NAC), BAPTA/AM, EGTA and H7 also have significant inhibitory effects on ROS generation. Finally, neither H7 nor NAC was able to affect the calcium response elicited by GA. Our results suggest that the causal signaling cascade during GA-inducted GRP78 expression occurs via a pathway that connects PLC to cytoplasmic calcium increase, PKC activation and, then, finally, ROS generation. Our data provides new insights into the influence of GA on ER stress response in 9L RBT cells.     

二次整数环上的ElGamal密码体制和签名方案

提出了二次数域的代数整数环上的ElGamal公钥密码体制和ElGamal签名方案,其安全性基于离散对数问题的困难性。