On Fri, May 15, 2020 at 2:04 PM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote: > > > > Looking at the code, I was wondering if the SHA-256 is really required > > > > here? It looks like it is using it as some kind of fingerprint to decide > > > > whether the provided file is identical to the one that has already been > > > > loaded. If this is the case, we should probably just use CRC32 instead. > > > > No, the binary blob carries data and possibly code. We are not only > > using the hash as a fingerprint but also an integrity check. > > > > But does it have to be cryptographically strong? Why is CRC32 not sufficient? Please see https://crrev.com/c/1490800/26/include/ec_commands.h#4744 for our original decision. Also would like to let you know that the data path to call calculate_sha256( ) is in-frequent (1~2 times) if you think it is too expensive to use SHA256.
