On 2012-4-23 06:51 , Ryan Schmidt wrote: > No, I'm trying to protect against the gzip compression of the tar archive > varying from generation to generation. gzip compression uses entropy -- > random numbers. If you have two identical tar archives, and gzip compress > them with the same settings, the resulting gzip files will not be byte for > byte identical, and thus they'll have different checksums: > > $ sha1sum *.tar > 92bfe8b02b49b977a18c9f8e8d301a0ef159fe51 1.tar > 92bfe8b02b49b977a18c9f8e8d301a0ef159fe51 2.tar > $ gzip 1.tar > $ gzip 2.tar > $ sha1sum *.tar.gz > 39c6beda6851d98295f770a11b8ea122647ae4c8 1.tar.gz > 7a95ea746e698d367ec155e4387972051e1a2e38 2.tar.gz > $
Nonsense. The gzip files in the above example differ because they contain files with different names. I haven't looked into it in detail, but I would guess the actual reason the tarballs end up having different checksums when regenerated is because of the timestamps. - Josh _______________________________________________ macports-dev mailing list macports-dev@lists.macosforge.org http://lists.macosforge.org/mailman/listinfo.cgi/macports-dev
