I want to be able to compress a file losslessly, and if the original file is identical to another user's file, I want both of our compressed files to match, even if the original file dates are different.
I want to use a maximum of 1GB of RAM while compressing. I'm leaning towards an asymmetric algorithm because the files I have are fairly large, and they take at least an hour to compress with LZMA1 "ultra" in 7-zip on a P4 machine with 1GB RAM and nothing else running. I think 7-zip and FreeARC can be used for my purposes. I've tried to find the commands I should be using, but I'm not having much luck.
edit: 100% identical files should be produced, even if the dates of creation are different. This should be possible through --nodates in Freearc, and with ???? in 7-zip. I'm looking for an equivalent command for 7-zip, and a way to standardize compression across multiple computers.