Data Acquisition

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Data Acquisition Data acquisition is the process of copying data. For computer forensics, it’s the task of collecting digital evidence from electronic media. There are two types of data acquisition: static acquisitions and live acquisitions. Static Acquisitions: if you have preserved the original media, making a second static acquisition should produce the same results. The data on the original disk is not altered, no matter how many times an acquisition is done. Your goal when acquiring data for a static acquisition is to preserve the digital evidence. Many times, you have only one chance to create a reliable copy of disk evidence with a data acquisition tool. Live acquisition: The future of data acquisitions is shifting toward live acquisitions because of the use of disk encryption with newer operating systems (OSs). In addition to encryption concerns, collecting any data that’s active in a suspect’s computer RAM is becoming more important to digital investigations. The processes and data integrity requirements for static and live acquisitions are the same. The only shortcoming with live acquisitions is not being able to perform repeatable processes, which are critical for collecting digital evidence. Although these tools are generally dependable, you should still take steps to make sure you acquire an image that can be verified. In addition, failures can and do occur, so you should learn how to use several acquisition tools and methods. Storage Formats: The data a computer forensics acquisition tool collects is stored as an image file in one of three formats. Two formats are open source and the third is proprietary. Each vendor has unique features, so several different proprietary formats are available. Depending on the ... ... middle of paper ... ...s. This tool, the dcfldd command, works similarly to the dd command but has many features designed for computer forensics acquisitions. The following are important functions dcfldd offers that aren’t possible with dd: • Specify hexadecimal patterns or text for clearing disk space. • Log errors to an output file for analysis and review. • Use the hashing options MD5, SHA-1, SHA-256, SHA-384, and SHA-512, with logging and the option of specifying the number of bytes to hash, such as specific blocks or sectors. • Refer to a status display indicating the acquisition’s progress in bytes. • Split data acquisitions into segmented volumes with numeric extensions (unlike dd’s limit of 99). • Verify the acquired data with the original disk or media data. References: • Guide to Computer Forensics and Investigations, Edition: 3rd, Nelson, Phillips, and Steuart; 2010; Cengage;

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