Meaning
Digital forensics relies on the direct, bit-stream duplication of a physical storage device to secure evidence. Performing a physical acquisition copies every sector, including deleted files, unallocated space, and hidden partitions. This method differs from logical extraction, which only copies visible file structures.
Hardware Interaction
Connection to the target media must bypass any active operating system to prevent data modification. During a physical acquisition, investigators use a hardware write-blocker to guarantee that no write commands reach the drive. This separation maintains the integrity of the original evidence.
Forensic Verification
Mathematical hash functions prove that the copied image is identical to the source drive. Before and after the physical acquisition, the software calculates hashes using algorithms like SHA-256. A matching pair of hashes confirms that no data was modified during the extraction.
Data Recovery
Unallocated space on a drive often contains fragments of deleted files that logical copies miss. By executing a physical acquisition, the analyst secures the raw blocks where these remnants reside. File carving software then scans the raw image to identify signature headers of common document formats.
This process reconstructs lost files that would otherwise remain inaccessible. It provides a comprehensive view of historical activity on the device.
