This creates a random 100 KiB buffer, and incrementally hashes
(SHA3-512) between 1 and 5 * Rate bytes in a loop, comparing the running
digest with the equivalent one shot call from the start of the buffer.

This is an eXtendable-Output Function with the following claimed
security strengths against *all* adversaries:

 Collision: min(d/2, 256)
 Preimage: >= min(d, 256)
 2nd Preimage: min(d, 256)

 where d is the amount of output used, in bits.

 * DIGEST_SHA3_[256,512] added as supported algorithms, which do
   exactly what is said on the tin.
 * test/bench now benchmarks all of the supported digest algorithms,
   so it's possible to see just how slow SHA-3 is, though the message
   sizes could probably use tweaking since this is very dependent on
   the message size vs the SHA-3 rate.

This is where things get tor specific.  It's just replacing stdint.h
and memset_s with the tor compat code so going back is trivial...

The digest routines use init/update/sum, where sum will automatically
copy the internal state to support calculating running digests.

The XOF routines use init/absorb/squeeze, which behave exactly as stated
on the tin.

As of commit: 64b6647514212b76ae7bca0dea9b7b197d1d8186

David Goulet authored 9 years ago and Nick Mathewson committed 9 years ago

Signed-off-by: David Goulet <dgoulet@ev0ke.net>

When we are low on accounted bandwidth, we stop advertising that
we're a directory, but we will continue to answer directory
requests, just as before.

Convention is that router_dump_router_to_string() should look at its
input "router", which should be generated by
router_build_fresh_descirptor().

Matthew Finkel authored 9 years ago and Nick Mathewson committed 9 years ago

Fixes #15801

Matthew Finkel authored 10 years ago and Nick Mathewson committed 9 years ago

This will give relay operators the ability of disabling the caching of
directory data. In general, this should not be necessary, but on some
lower-resource systems it may beneficial.

Matthew Finkel authored 10 years ago and Nick Mathewson committed 9 years ago

Final piece of prop 237. Closes 12538.

This is CID 1343603

This is CID 1343601.

This is CID 1340255

This is CID 1340251