Comment on Order
dan@lemm.ee 1 year agoLossless compression algorithms aren’t magical, they make some data bigger and some data smaller, the trick is that the stuff they make smaller happens to match common patterns. Given truly random data, lossless compression algorithms will make the data larger.
A good encryption algorithm will output data that’s effectively indistinguishable from randomness.
Put those two facts together and it’s pretty easy to see why you should compress first then encrypt.
bastian_5@sh.itjust.works 1 year ago
And the fact that it can grow data means you should really put a test to make sure that the compressed data is actually smaller… I once had something refuse to allow me to upload a file that was well below their 8Mb file limit while it was claiming it was above the limit, and I’m assuming it was because they were testing the size after compression and that file grew from 6Mb to above the limit.