You have to convey which algorithm, which takes bits. And at the very least you need a pointer to a file, which also takes bits. You’d do well to look for archi

You have to convey which algorithm, which takes bits. And at the very least you need a pointer to a file, which also takes bits. You’d do well to look for archives of alt.comp.compression. There was also a classic thread that surfaced recently on HN about a compression challenge whereby someone tried to disengenuously attempt to compress a file of random data (uncompressable by definition) by splitting it on a character then deleting that character from each file. Was a simple algorithm, that appeared to require fewer bits to encode. The problem is, all this person did was shift the bits to the filesystem’s metadata, which is not obvious from the command line. The final encoding ended up taking more bits once you take said metadata into account.