What is the primary technique used to recover files from unallocated space by identifying file headers?

The primary technique used to recover files from unallocated space by identifying file headers is data carving. This process involves analyzing the data stored in unallocated space to locate and reconstruct files, even if the file system no longer tracks them. Data carving identifies unique patterns or "headers" that indicate the beginning of a file, allowing forensic investigators to piece together fragments of files based on the known signatures of various file types.

By focusing on the file headers, which contain critical information about the file's type and structure, data carving can effectively reconstruct files that have been deleted or are otherwise inaccessible through traditional means. This technique is especially useful when the original file system metadata is unavailable due to deletion or corruption.