An Efficient Piecewise Hashing Method for Computer Forensics
ABSTRACT Hashing, a basic tool in computer forensics, is used to ensure data integrity and to identify known data objects efficiently. Unfortunately, intentional tiny modified file can not be identified using this traditional technique. Context triggered piecewise hashing separates a file into pieces using local context characteristic, and produces a hash sequence as a hash signature. The hash signature can be used to identify similar files with tiny modifications such as insertion, replacement and deletion. The algorithm of currently available scheme is designed for junk mail detection, which is low efficient and not suitable for file system investigation. In this paper, an improved algorithm based on the Store-Hash and Rehash idea is developed for context triggered piecewise hashing technique. Experiment results show that the performance of speed and the ability of similarity detection of the new scheme are better than that of spamsum. It is valuable for forensics practice.
- SourceAvailable from: Aleksandar Jevremovic
- "The DMS model is simple to use and can be relatively easily integrated in Web servers and browsers. It is also general in the sense that its main idea with small modifications can be used in other problem domains such as routing, load balancing, and computer forensics . Obvious subject of future work is a software implementation of DMS and evaluation of its efficiency in production environments. "
Article: DMS — Improving Web performance[Show abstract] [Hide abstract]
ABSTRACT: In this paper we consider the problem of improving Web performance and propose an efficient differencing and merging system (DMS) based on an HTTP protocol extension. To provide for faster information exchange over the Web, the system tries to transfer only computed differences between requested documents and previously retrieved documents from the same site. Analysis and experimental results prove the effectiveness of DMS, but also show bigger processor and memory load on servers and clients. DMS is compatible with most of the existing solutions for improving Web performance. Moreover, SSL security system may be used to provide Web privacy and authenticity. The DMS model is simple to use and can be relatively easily integrated in Web servers and browsers.
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ABSTRACT: A hash function is a well-known method in computer science to map arbitrary large data to bit strings of a fixed short length. This property is used in computer forensics to identify known files on base of their hash value. As of today, in a pre-step process hash values of files are generated and stored in a database; typically a cryptographic hash func-tion like MD5 or SHA-1 is used. Later the investigator computes hash values of files, which he finds on a storage medium, and performs look ups in his database. Due to security properties of cryptographic hash functions, they can not be used to identify similar files. Therefore Jesse Kornblum proposed a similarity preserving hash function to identify sim-ilar files. This paper discusses the efficiency of Kornblum's approach. We present some enhancements that increase the performance of his algo-rithm by 55% if applied to a real life scenario. Furthermore, we discuss some characteristics of a sample Windows XP system, which are relevant for the performance of Kornblum's approach.
Conference Paper: Information Assurance and Forensic Readiness.[Show abstract] [Hide abstract]
ABSTRACT: Egalitarianism and justice are amongst the core attributes of a democratic regime and should be also secured in an e-democratic setting. As such, the rise of computer related offenses pose a threat to the fundamental aspects of e-democracy and e-governance. Digital forensics are a key component for protecting and enabling the underlying (e-)democratic values and therefore forensic readiness should be considered in an e-democratic setting. This position paper commences from the observation that the density of compliance and potential litigation activities is monotonically increasing in modern organizations, as rules, legislative regulations and policies are being constantly added to the corporate environment. Forensic practices seem to be departing from the niche of law enforcement and are becoming a business function and infrastructural component, posing new challenges to the security professionals. Having no a priori knowledge on whether a security related event or corporate policy violation will lead to litigation, we advocate that computer forensics need to be applied to all investigatory, monitoring and auditing activities. This would result into an inflation of the responsibilities of the Information Security Officer. After exploring some commonalities and differences between IS audit and computer forensics, we present a list of strategic challenges the organization and, in effect, the IS security and audit practitioner will face.Next Generation Society. Technological and Legal Issues - Third International Conference, e-Democracy 2009, Athens, Greece, September 23-25, 2009, Revised Selected Papers; 01/2009