SHA3 is still waiting for final standardization.
Although this is looking less likely given
https://www.cdt.org/blogs/joseph-lorenzo-hall/2409-nist-sha-3
In the meantime, cryptohash implements skein, and it's used by some of the
haskell ecosystem (for yesod sessions, IIRC), so this implementation is
likely to continue working. Also, I've talked with the cryprohash author
and he's a reasonable guy.
It makes sense to have an alternate high security hash, in case some
horrible attack is found against SHA2 tomorrow, or in case SHA3 comes out
and worst fears are realized.
I'd also like to support using skein for HMAC. But no hurry there and
a new version of cryptohash has much nicer HMAC code, so I will probably
wait until I can use that version.
However, this is not working for gcrypt repos with a mangled hostname.
Problem is that the locked down key is installed before the repo is
initialized, so git-annex-shell refuses to allow the gcrypt special remote
to do its setup.
gcrypt needs to be able to fast-forward the master branch. If a git
repository is set up with git init --shared --bare, it gets that set, and
pushing to it will then fail, even when it's up-to-date.
recvkey was told it was receiving a HMAC key from a direct mode repo,
and that confused it into rejecting the transfer, since it has no way to
verify a key using that backend, since there is no HMAC backend.
I considered making recvkey skip verification in the case of an unknown
backend. However, that could lead to bad results; a key can legitimately be
in the annex with a backend that the remote git-annex-shell doesn't know
about. Better to keep it rejecting if it cannot verify.
Instead, made the gcrypt special remote not set the direct mode flag when
sending (and receiving) files.
Also, added some recvkey messages when its checks fail, since otherwise
all that is shown is a confusing error message from rsync when the remote
git-annex-shell exits nonzero.
recvkey was told it was receiving a HMAC key from a direct mode repo,
and that confused it into rejecting the transfer, since it has no way to
verify a key using that backend, since there is no HMAC backend.
I considered making recvkey skip verification in the case of an unknown
backend. However, that could lead to bad results; a key can legitimately be
in the annex with a backend that the remote git-annex-shell doesn't know
about. Better to keep it rejecting if it cannot verify.
Instead, made the gcrypt special remote not set the direct mode flag when
sending (and receiving) files.
Also, added some recvkey messages when its checks fail, since otherwise
all that is shown is a confusing error message from rsync when the remote
git-annex-shell exits nonzero.
