you are massively prematurely optimizing, the vast majority of torrents are greater than a few hundred megabytes, nobody cares about the overhead of a few KB of

you are massively prematurely optimizing, the vast majority of torrents are greater than a few hundred megabytes, nobody cares about the overhead of a few KB of hashes, you are already hashing data when you download or upload it, adding in another hash when data is fresh in the CPU cache is basically free.