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Book Overview & Buying
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Table Of Contents
Digital Forensics Cookbook
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As we acquire data, we must validate it so we can prove the evidence stayed bit-for-bit identical during handling, transfer, or analysis. A cryptographic hash acts as a digital fingerprint for a file or image. Compute it immediately after acquisition, record the hash value generated, then recompute whenever the file is copied or moved to show the data is unchanged. If even one binary bit has changed, the resultant hash value will not match. This provides reproducible, mathematical proof to validate that our data has remained unaltered. Many acquisition tools (for example FTK Imager) compute hashes automatically; you can also compute them independently with other software utilities when needed.
In this recipe, we will validate acquired data by computing and comparing cryptographic hash values. You will use a hashing utility to demonstrate how identical files produce matching hashes and how even minor changes result in different values, confirming data integrity.