handprinting

handprinting
 n.— «The “Similarity” portion of SET comes from the realization that many of the files being shared contain pieces of identical data. Examples include music files that differ only in terms of tags, movies or movie trailers that are dubbed in different languages, and updated versions of software. Like other P2P systems, SET divides large files into small segments. Once that process is complete, however, the SET software searches for similar files using a method called “handprinting,” which is similar to the pattern matching techniques used to cluster search results or filter spam. Once similar files are identified, they are scanned for any individual chunks that are identical to pieces of the file being downloaded.» —“Similarity searches accelerate P2P downloads by 30-70 percent” by John Timmer Ars Technica Apr. 10, 2007. (source: Double-Tongued Dictionary)