64 bytes for the hash in `crypto_box_curve25519xsalsa20poly1305_seed_keypair(..)`?
getify opened this issue · 1 comments
getify commented
I'm trying to understand this line:
The rest of that function only uses 32 bytes, so I'm wondering what's the significance/reason for declaring the hash
to be 64 bytes wide instead of 32 bytes?
Is it because the [sha512(..)
function}(https://github.com/jedisct1/libsodium/blob/4cdcefaff250af42663eb202c1daf49ea4d7ad7e/src/libsodium/crypto_hash/sha512/cp/hash_sha512_cp.c#L274) actually needs/uses all 64 bytes for is operation, even though we only end up using the first 32 bytes from it?
jedisct1 commented
Yes, the output of the sha512 function is 64 bytes, so a 64 byte buffer is needed.
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