网络数据通信中的隐蔽通道技术

随着科学技术的不断发展,网络技术也发生了日新月异的变化。文章通过对网络数据通信中的隐蔽通道技术的介绍,进一步就网络通信中隐蔽通道存在的技术基础和实现原理进行了探讨,并对网络通信隐蔽通道技术进行了深入的研究与分析。与此同时对隐蔽通道的检测技术进行了讨论,提出了一系列针对网络安全的防范措施。     

网络隐蔽通道及其识别技术研究

介绍网络隐蔽通道及其识别技术.在对网络隐蔽通道概念、原理和分类进行具体介绍的基础上,提出特征匹配、协议异常分析和行为异常分析三种隐蔽通道检测技术,并具体介绍了一个针对行为异常分析检测技术的典型应用.文中就网络隐蔽通道检测技术提出的三种手段相结合的思路具有较高的实用性和一定的创新性,已在实际应用中取得了较好的效果.     

安全操作系统中隐蔽通道的研究

安全操作系统是信息系统安全的基础,隐蔽通道是解决操作系统安全的瓶颈。论文首先介绍了一种对隐蔽存储通道进行细分的方法,即把隐蔽存储通道分为直接隐蔽存储通道和间接隐蔽存储通道。接着在对隐蔽通道进一步分析的基础上,给出了隐蔽通道产生的充要条件。     

泛在网络环境下隐蔽通道关键技术研究综述

在泛在网络环境下,隐蔽通道通过修改系统共享资源,绕开系统的安全策略传输隐蔽信息,给计算机和网络系统造成了严重的安全威胁.针对此问题,主要从度量、构建和检测3个方面对泛在网络环境下的隐蔽通道相关研究进行归纳和分析.首先,总结归纳了典型的隐蔽通道度量指标,包括隐蔽通道的容量、稳健性、抗检测性、规律性和形状.其次,归纳整理了...     

基于DNS的隐蔽通道流量检测

为提出一种有效检测各类型DNS隐蔽通道的方法,研究了DNS隐蔽通信流量特性,提取可区分合法查询与隐蔽通信的12个数据分组特征,利用机器学习的分类器对其会话统计特性进行判别。实验表明,决策树模型可检测训练中全部22种DNS隐蔽通道,并可识别未经训练的新型隐蔽通道。系统在校园网流量实际部署中成功检出多个DNS隧道的存在。     

基于概率干扰的概率隐蔽通道仿真研究

讨论了影响概率隐蔽通道带宽和传输错误率的因素,对不满足BSPNI(bi-simulation strong probabilistic non-interference)、PBNDC (probabilistic non-deducibility on composition)和SPBNDC (strong probabilistic BNDC)性质的系统概率隐蔽通道进行了仿真,仿真结果表明,概率隐蔽通道的带宽与硬/软件配置、概率调度因子和调度次数有密切关系,当硬/软件配置和概率调度因子固定时,概率隐蔽通道的带宽近似地反比于调度次数;传输错误率与概率调度因子和调度次数关系密切,调度次数越大,传输错误率越小.     

一个安全操作系统SLinux隐蔽通道标识与处理

标识与处理隐蔽通道是美国橘皮书TCSEC对B2及以上级别安全产品的关键评估要求,也是国际标准CC评估EAL5及以上系统的关键指标.本文基于安全操作系统SLinux的设计开发实践,给出一个安全系统隐蔽通道的标识方案、分析流程、分析结果,论述了隐蔽通道带宽计算的关键点,探讨了隐蔽通道标识与处理方案.     

AJAX技术下隐蔽通道的安全设计

通过Internet,在使用AJAX方式下载文件的代码中调整存储路径,会导致在文件下载进程中,存在隐蔽存储通道的问题,隐蔽通道的存在会给信息安全带来隐患。为提高下载信息的安全性和可靠性,通过分析隐蔽通道处理技术,对隐蔽通道的存在进行改进,并设计了一种安全模型,对下载的数据信息进行隐蔽存储通道的消除和过滤,通过MD5值验证下载信息的完整,为网络下载中确保信息数据的安全性和可信性提供保障。     

一种支持事务内I/O操作的事务存储系统结构

本文提出了一种支持事务内I/O操作的硬件事务存储系统结构.该系统基于多核处理器结构和已有的cache一致性机制,通过增加事务缓冲区和相关硬软件,实现对事务的支持.事务内I/O操作的实现基于事务提交锁的部分提交以及事务线程的阻塞/唤醒机制,解决了事务内I/O操作所面临的回滚、事务迁移和缓冲区溢出等问题.系统在模拟器中实现,并利用5个测试程序对系统的性能进行了评价分析,结果表明事务程序在系统中的性能相对于锁程序得到提升.     

超薄的金属/LB绝缘膜/半导体结构的CV和I-V特性

本文研究了超薄的金属/LB绝缘膜/半导体(MLS)结构的C-V和I-V特性,理论分析与实验结果相一致,结论如下:(1)超薄MLS结构具有正常的C-V特性和I-V特性;(2)以LB薄膜作为绝缘层可调整肖特基器件势垒高度。     

Quantifying and Classifying Covert Communications on Android

By exploiting known covert channels, Android applications today are able to bypass the built-in permission system and share data in a potentially untraceable manner. These channels have sufficient bandwidth to transmit sensitive information, such as GPS locations, in real-time to collaborating applications with Internet access. In this paper, we extend previous work involving an application layer covert communications detector. We measure the stability of the volume and vibration channels on the Android emulator, HTC G1, and Motorola Droid. In addition, we quantify the effect that our detector has on channel capacities for stealthy malicious applications using a theoretical model. Lastly, we introduce a new classification of covert and overt communication for the Android platform.     

基于多版本的多级安全并发控制机制的研究

在多级安全数据库系统中，如果采用传统的并发控制机制，则通过多级事务的协作可以很容易的创建隐通道，因此我们必须研究适合于多级安全数据库的并发控制机制。本文提出了一个基于多版本的安全的并发控制机制，它能阻止隐通道的创建而不会导致检索异常和高级事务的饿死，同时还能提供一个多级事务的可串行化调度。     

一种数据挖掘算法在入侵检测系统中的应用

文章讲述了一种基于关联规则的数据挖掘算法在入侵检测系统中的应用。首先得到一些数据库日志中的强关联规则，然后以此作为判断攻击性事务的标准，最后用实验说明了该算法的有效性。     

Heterogeneous distributed database management: The HD-DBMS

The proliferation of different DBMS and advances in computer networking and communications have led to increasing heterogeneous distributed DBMS network scenarios. Major heterogeneity problems and challenges include: different database models, syntactically and semantically different DBMS, different types of controls (recovery, etc.), etc. We address herein the long-range goal for a heterogeneous distributed DBMS (HD-DBMS) to be able to support a network in which any user in any node can be given an integrated and tailored view or schema, while in reality the data may reside in one single database or in physically separated databases, managed individually by the same type of DBMS (by the only one the user understands) or by different DBMS. We cite the major approaches to data sharing and accessing: from the primitive commercial file and database unload/load and PC download, to common interfaces on top of existing DBMS, to the R&D and prototype efforts toward the long-range desires. Commercial availability of the more encompassing thrusts may become a reality with the mounting problems, opportunity costs, and demand for data sharing in the heterogeneous world. Major research and development projects in this arena are leading toward some partial attainment of the long-range objective. The UCLA HD-DBMS project is highlighted herein, with a presentation of its status, progress, and plans. It is a longer range project, with the unique feature of allowing any user in the network to use a preferred database model and DML to access or update any data in the heterogeneous network. HD-DBM5 is to provide a multilingual interface to heterogeneous distributed databases.     

电波数据库用数据库管理系统的选择

本文介绍了电波传播数据库的任务，技术特点和有关开发情况。据此需要选择一个性能优劣的数据库管理系统。     

一种数据库加密系统的研究与实现

主要是从数据库管理系统这个层次框架对OS层、DBMS内核层和DBMS外层三不同层次对数据库数据的加密技术进行了简单介绍.通过对数据库和加密技术的研究,确立了基于记录和字段的密钥生成函数.并在最后提出了基于DBMS外层的一种数据库加密系统的实现方案.     

Recovery of business intelligence systems: Towards guaranteed continuity of patient centric healthcare systems through a matrix-based recovery approach

With the intensive use of the internet, patient centric healthcare systems shifted away from paper-based records towards a computerized format. Electronic patient centric healthcare databases contain information about patients that should be kept available for further reference. Healthcare databases contain potential data that makes them a goal for attackers. Hacking into these systems and publishing their contents online exposes them to a challenge that affects their continuity. Any denial of this service will not be tolerated since we cannot know when we need to retrieve a patient’s record. Denial of service affects the continuity of the healthcare system which in turn threatens patients’ lives, decreases the efficiency of the healthcare system and increases the operating costs of the attacked healthcare organization. Although there are many defensive security methods that have been devised, nonetheless malicious transactions may find a way to penetrate the secured safeguard and then modify critical data of healthcare databases. When a malicious transaction modifies a patient record in a database, the damage may spread to other records through valid transactions. Therefore, recovery techniques are required. The efficiency of the data recovery algorithm is substantial for e-healthcare systems. A patient cannot wait too long for his/her medical history to be recovered so that the correct medication be prescribed. Nevertheless, in order to have fast data recovery, an efficient damage assessment process should precede the recovery stage. The damage assessment must be performed as the intrusion detection system detects the malicious activity. The execution time of the recovery process is a crucial factor for measuring the performance because it is directly proportional to the denial of service time of any healthcare system. This paper presents a high performance damage assessment and recovery algorithm for e-healthcare systems. The algorithm provides fast damage assessment after an attack by a malicious transaction to keep the availability of the e-healthcare database. Reducing the execution time of recovery is the key target of our algorithm. The proposed algorithm outperforms the existing algorithm. It is about six times faster than the most recent proposed algorithm. In the worst case, the proposed algorithm takes 8.81?ms to discover the damaged part of the database; however, the fastest recent algorithm requires 50.91?ms. In the best case, the proposed algorithm requires 0.43?ms, which is 86 times faster than the fastest recent work. This is a significant reduction of execution time compared with other available approaches. Saving the damage assessment time means shorter denial of service periods, which in turn guarantees the continuity of the patient centric healthcare system.     

Identification of DNS covert channel based on improved convolutional neural network

In order to effectively identify the multiple types of DNS covert channels,the implementation of different sorts of DNS covert channel software was studied,and a detection based on the improved convolutional neural network was proposed.The experimental results,grounded upon the campus network traffic,show that the detection can identify twenty-two kinds of data interaction modes of DNS covert channels and is able to identify the unknown DNS covert channel traffic.The proposed method outperforms the existing methods.     

数字电视网络隐蔽信道技术研究

目前针对隐蔽信道的研究工作大部分都基于互联网协议,在数字电视中实现隐蔽通信是信息隐藏技术的一个新方向。论文在隐蔽信道信息传递框架的基础上,阐明了数字电视网络中隐蔽信道存在的可能性和必然性。本文提出了基于TS包的填充域与PCR域保留位的信息隐藏方法,并实现仿真,然后对两种隐藏方案的性能进行了分析与比较。研究工作对在数字电视网络中构建隐蔽信道有一定的指导意义。     

基于区块链的社会物联网可信服务管理框架

针对当前社会物联网可信服务管理中存在的中心化程度高、交易不透明和易受攻击等问题,提出了一种基于区块链的社会物联网可信服务管理框架。该框架通过区块链的去中心化特性在服务请求者和服务提供者之间直接建立信任关系,利用智能合约产生并管理新的交易,实现交易过程透明化并减少管理维护成本。同时,区块链的共识机制可用于交易验证并防范恶意攻击和篡改,减少网络攻击和恶意节点的欺骗。最后,分析了该框架在实际构建中面临的主要挑战。