数字图像模糊滤波盲取证算法

数字图像模糊滤波操作常用于美化润饰“伪造”图像.针对常用的均值滤波、空域高斯低通滤波与中值滤波,提出了一种能同时检测上述3种操作的盲取证算法.首先将高频残差作为特征提取域,然后分别基于二值局部模式LBP和自回归模型提取特征,最后使用支持向量机构造模糊滤波检测器.实验结果表明,所提算法能有效地检测模糊滤波操作,对抗JPEG压缩的鲁棒性能较好.     

热泵精馏隔壁塔分离宽沸程物系的模拟

将中间换热和热泵精馏两种精馏节能技术应用到隔壁塔中,提出了带中间换热器的热泵精馏隔壁塔流程,以解决隔壁塔在分离宽沸程物系时出现的塔顶与塔底温差过高而不宜应用热泵精馏的问题。利用精馏塔总复合曲线图,可确定中间产品塔板采出流股的相态,从而得到不同类型的热泵精馏隔壁塔流程。宽沸程物系分离实例的模拟计算结果表明,该类流程在主塔气液相流量较大的情况下具有较高的节能效率。     

Instagram Mobile Application Digital Forensics

In this research, we developed a plugin for our automated digital forensics framework to extract and preserve the evidence from the Android and the IOS-based mobile phone application, Instagram. This plugin extracts personal details from Instagram users, e.g., name, user name, mobile number, ID, direct text or audio, video, and picture messages exchanged between different Instagram users. While developing the plugin, we identified resources available in both Android and IOS-based devices holding key forensics artifacts. We highlighted the poor privacy scheme employed by Instagram. This work, has shown how the sensitive data posted in the Instagram mobile application can easily be reconstructed, and how the traces, as well as the URL links of visual messages, can be used to access the privacy of any Instagram user without any critical credential verification. We also employed the anti-forensics method on the Instagram Android’s application and were able to restore the application from the altered or corrupted database file, which any criminal mind can use to set up or trap someone else. The outcome of this research is a plugin for our digital forensics ready framework software which could be used by law enforcement and regulatory agencies to reconstruct the digital evidence available in the Instagram mobile application directories on both Android and IOS-based mobile phones.     

Applying of Switch Strong Tracking UKF in Spacecraft Autonomous Celestial Navigation

Star & Horizon sensor based autonomous navigation methods play an increasingly important role in spacecraft celestial navigation. However,the measurements of star sensors and horizon sensor are frequently affected by uncertain noises from space environment. To improve the estimation precision,a state estimation algorithm named Switch Strong Tracking Unscented Kalman Filter( SSTUKF) is presented. Firstly,the adaptive fading factor is deduced through the adoption of unknown instrumental diagonal matrixes to real time rectify the measurement covariance matrix. Secondly,according to the deduction of Chebyshev law of large numbers,innovation criterion is introduced during estimation to decrease the unnecessary calculation. Finally,SSTUKF is suggested through the adoption of adaptive fading factor and innovation criterion. The filter can switch between the normal filter mode and adaptive filter mode. As the calculation of innovation criterion is less than the adaptive fading factor,SSTUKF improves the estimation efficiency. To demonstrate the effectiveness,SSTUKF is applied to Star & Horizon sensor based autonomous navigation system with uncertain measurement noises. The simulation results verify the proposed algorithm.     

基于数据挖掘的Multi-Agent动态取证系统研究

研究了计算机动态取证的相关技术,提出了一个计算机动态取证系统模型并对相关模块进行设计。根据动态取证的特点,将数据挖掘技术和多智能代理技术结合起来应用于动态取证系统中,系统在体系结构上使用基于智能代理的分布式结构,采用数据挖掘技术进行动态取证的海量数据分析,针对基本挖掘算法在取证分析实际应用中可能存在的不足,提出了相应的改进方法,通过实验分析,证明了改进算法在动态取证应用中的有效性。     

Android移动终端取证综述

随着移动智能终端的普及,利用移动终端进行欺骗,敲诈的犯罪刑事案件正在呈现逐年上涨的趋势,对移动终端的深入取证工作迫在眉睫。为了开展后续研究,先对Android移动终端的取证研究现状,取证工具,取证技术进行概述,分析对比国内外的研究成果,提出下一步研究计划。     

网络文化信息监控与取证的核心技术研究

网络信息监控与取证的核心技术是目前保障网络安全最有效的应用技术。针对网络文化信息监控的需要和监控的特点,在现有监控技术基础上,对监控与取证技术的新内涵进行了简要介绍,对几种监控与取证的核心技术进行了仿真分析,采用原理推论的方法,得出了5种监控应用技术的应用范围、适用性及其特点,以及监控与取证的最终目的在于信息审计与证据留存的结论,提出了在线监控网络文化信息系统建设的新的建议。     

数字音视频取证系统中的视频压缩技术简介

介绍了在远程视频网络传输中发挥着重要作用的高性能视频压缩技术,对主流的视频压缩标准M-JPEG、MPEG4和H.264进行了讨论。基于这三种标准编码方案,将高性能的视频编码应用到了所开发的网络式数字音视频取证系统中,取得了较好的效果。     

InnoDB database forensics: Enhanced reconstruction of data manipulation queries from redo logs

The InnoDB storage engine is one of the most widely used storage engines for MySQL. This paper discusses possibilities of utilizing the redo logs of InnoDB databases for forensic analysis, as well as the extraction of the information needed from the MySQL definition files, in order to carry out this kind of analysis. Since the redo logs are internal log files of the storage engine and thus cannot easily be changed undetected, this forensic method can be very useful against adversaries with administrator privileges, which could otherwise cover their tracks by manipulating traditional log files intended for audit and control purposes. Based on a prototype implementation, we show methods for recovering Insert, Delete and Update statements issued against a database.     

电子证据收集与还原系统的设计与实现

随着计算机技术的发展,借助计算机及网络等高科技的犯罪事件逐年增加,危害也越来越大。为了打击计算机犯罪,计算机取证技术应运而生。文章设计并实现了一款基于Windows的电子证据收集与还原系统。该系统主要采用AES算法,基于RSA的数字签名、MD5散列算法及密钥分配与管理等技术,实现从海量信息中有效快速地收集电子证据,同时还确保了电子证据从提取到分析过程中的有效性、完整性和防篡改性,使得收集的电子证据更具有证明力。通过测试与分析,证明了该系统设计合理、效率高、操作简单,具有很强的实用性。