If you’re worried about bit-flipping, you could just store multiple copies of the hash and then do voting, since it’s small. If you’re worried about correlated sources of error that helps less, though.
As someone with no storage expertise I'm curious, does anyone know the likelyhood of an error resulting in a bit flip rather than an unreadable sector? Memory bit flips during I/O are another thing but I'd expect a modern HDD/SSD to return an error if it isn't sure about what it's reading.
Thanks for the link. I think that 10^14 figure is the likelyhood of the disk error correction failing to produce a valid result from the underlying media, returning a read error and adding the block to pending bad sectors. A typical read error that is caught by the OS and prompts the user to replace drives.
What I understand by bit flip is a corruption that gets past that check (ie the "flips balance themselves" and produce a valid ECC) and returns bad data to the OS without producing any errors. Only a few filesystems that make their own checksums (like ZFS) would catch this failure mode.
It's one reason I still use ZFS despite the downsides, so I wonder if I'm being too cautious about something that essentially can't happen.
(but then the .torrent file itself has to be stored on a storage that resists bit flipping)