Editing Deflate (section)

{{Short description|Data compression algorithm}}
{{About|the data compression algorithm||Deflation (disambiguation)}}
{{Original research|date=May 2025}}
{{Infobox file format
| name = Deflate
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| extension = <!-- or: | extensions = -->
|_nomimecode = 
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| developer = [[Phil Katz]], [[PKWare]]
| released = {{Start date and age|1990|08|21|df=yes}}
| latest_release_version = 
| latest_release_date = <!-- {{Start date and age|202y|mm|dd|df=yes}} -->
| type = 
| compression = [[LZ77 and LZ78|LZ77]], [[Huffman coding]]
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| standard = <!-- or: | standards = -->
| free = Yes
| open = Yes
| url = {{URL|www.pkware.com}}
}}

In [[computing]], '''Deflate''' (stylized as '''DEFLATE''', and also called '''Flate'''<ref>{{cite web |author1=The Go Authors |title=flate package - compress/flate - Go Packages |url=https://pkg.go.dev/compress/flate |website=The Go Programming Language |publisher=Google |access-date=5 September 2023 |quote=Package flate implements the Deflate compressed data format, described in RFC issue 1951.}}</ref><ref>{{cite web |author1=<!-- Human Name --> |author1-link= |title=PDF 32000-1:2008: Document management — Portable document format — Part 1: PDF 1.7 |url=https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf |website=Adobe Open Source |publisher=[[Adobe Inc.]] |access-date=5 September 2023 |page=23 |quote=FlateDecode [...] Decompresses data encoded using the zlib/deflate compression method}}</ref>) is a [[Lossless compression|lossless]] [[data compression]] [[file format]] that uses a combination of [[LZ77 and LZ78|LZ77]] and [[Huffman coding]]. It was designed by [[Phil Katz]], for version 2 of his [[PKZIP]] archiving tool. Deflate was later specified in [[Request for Comments]] (RFC) 1951 (1996).<ref name="IETF">{{cite IETF |last1=Deutsch |first1=L. Peter |author1-link=L. Peter Deutsch |date=May 1996 |title=Deflate Compressed Data Format Specification version 1.3 |rfc=1951 |section=Abstract |page=1 |publisher=[[Internet Engineering Task Force]] (IETF) |access-date=2014-04-23}}</ref>

Katz also designed the original [[algorithm]] used to construct Deflate streams. This algorithm received [[software patent]] {{US patent|5051745}}, assigned to [[PKWare]], Inc.<ref name="patent">{{cite patent |country=US |number=5051745 |inventor1-last=Katz |inventor1-first=Phillip W. |inventorlink1=Phil Katz |status=patent |publication-date=1991-09-24 |issue-date=1991-09-24 |title=String Searcher, and Compressor Using Same |assign1=PKWare Inc.}}</ref><ref>{{cite book |last1=Salomon |first1=David |year=2007 |title=Data Compression: The Complete Reference |edition=4 |page=241 |publisher=Springer |isbn=978-1-84628-602-5 |url=https://books.google.com/books?id=ujnQogzx_2EC&pg=PA241}}</ref> As stated in the RFC document, an algorithm producing Deflate files was widely thought to be implementable in a manner not covered by patents.<ref name="IETF"/> This led to its widespread use. For example, in [[gzip]] compressed files and Portable Network Graphics ([[PNG]]) image files, in addition to the [[ZIP (file format)|ZIP]] file format for which Katz originally designed it. The patent has since expired.