@javiergutierrezchamorro ZipMix (close to public-domain, if I read the comments right, & source-archive also located there) would possibly be useful as an optional part of the ZIP tool-chain, though intermediate results from the whole chain would have to be kept (usually not an issue on today's multi-TB drives), & also would have to careful to perform exactly sufficient # of comparisons. Good news: ZipMix would likely be among the fastest tools in the chain!