Editing ZIP (file format) (section)

=== Compression methods ===
The .ZIP File Format Specification documents the following compression methods: Store (no compression), Shrink ([[LZW]]), Reduce (levels 1–4; LZ77 + probabilistic), Implode, Deflate, Deflate64, [[bzip2]], [[LZMA]], [[Zstandard]], [[WavPack]], [[Prediction by Partial Matching|PPMd]], and a LZ77 variant provided by [[IBM z/OS]] CMPSC instruction.<ref>{{cite web|author=Adler, Mark|title=How are zlib, gzip and zip related? What do they have in common and how are they different?|url=https://stackoverflow.com/a/20765054/233286|access-date=2018-11-27}}</ref><ref name="zip6310"/> The most commonly used compression method is [[DEFLATE]], which is described in IETF {{IETF RFC|1951}}.

Other methods mentioned, but not documented in detail in the specification include: PKWARE DCL Implode (old IBM TERSE), new [[Terse|IBM TERSE]], IBM LZ77 z Architecture (PFS), and a JPEG variant. A "Tokenize" method was reserved for a third party, but support was never added.<ref name="zip635"/>

The word ''Implode'' is overused by PKWARE: the DCL/TERSE Implode is distinct from the old PKZIP Implode, a predecessor to Deflate. The DCL Implode is undocumented partially due to its proprietary nature held by IBM, but [[Mark Adler]] has nevertheless provided a decompressor called "blast" alongside zlib.<ref>{{cite web |title=Frequently Asked Questions about zlib |url=https://www.zlib.net/zlib_faq.html |website=zlib |quote=The PKWare DCL uses a completely different compressed data format than does PKZIP and zlib. However, you can look in zlib's  contrib/blast directory for a possible solution to your problem.}} ([https://github.com/madler/zlib/tree/master/contrib/blast contrib/blast])</ref>