For steady-state operation, this reduces the average time between wallet disk
writes from once per block to once per hour.
On -rescan, witness caches are only written out at the end along with the best
block, increasing speed while ensuring that on-disk state is kept consistent.
Witness caches are now never recreated during a -reindex, on the assumption that
the blocks themselves are not changing (the chain is just being reconstructed),
and so the witnesses will remain valid.
Part of #1749.
Process verification keys to perform online verification
Checking proofs involves some arithmetic with pairings using components of the proof and the verification key. If you already have some curve points, like those in the verification key, you can amortize the cost of some of the more expensive arithmetic.
This PR adopts libsnark's precomputation of G2 elements in the verification key.
We *currently* call `r1cs_ppzksnark_verifier_strong_IC`:
```c++
template<typename ppT>
bool r1cs_ppzksnark_verifier_strong_IC(const r1cs_ppzksnark_verification_key<ppT> &vk,
const r1cs_ppzksnark_primary_input<ppT> &primary_input,
const r1cs_ppzksnark_proof<ppT> &proof)
{
enter_block("Call to r1cs_ppzksnark_verifier_strong_IC");
r1cs_ppzksnark_processed_verification_key<ppT> pvk = r1cs_ppzksnark_verifier_process_vk<ppT>(vk);
bool result = r1cs_ppzksnark_online_verifier_strong_IC<ppT>(pvk, primary_input, proof);
leave_block("Call to r1cs_ppzksnark_verifier_strong_IC");
return result;
}
```
Notice that this merely performs precomputation of the verification key, and then calls `r1cs_ppzksnark_online_verifier_strong_IC`. This PR merely performs the precomputation during verification key initialization, and calls that function directly.
Zcash zk-SNARK public parameters for 1.0 "Sprout".
Created in the ceremony this weekend! 🎉
We're writing a blog post about this, I'm going to publish the code shortly too.
Closes#1553
New private/public key pairs for broadcasting alert messages
Implements #424
Fixes and integrates method of sending alerts as described by upstream here:
- https://gist.github.com/laanwj/0e689cfa37b52bcbbb44
To send an alert:
- Copy private keys into alertkeys.h.
- Modify alert parameters and message found in sendalert.cpp
- Build and run to send the alert e.g. ./zcashd -printtoconsole -sendalert
Tested and verified with local nodes on alpha 6 testnet.
Final changes to the circuit
* Remove [redundant](https://github.com/scipr-lab/libsnark/issues/37) bitness constraints that I pointed out in #908.
* The depth is increased from 20 to 29. I chose 29 because the QAP degree ends up being a power of two, which is probably going to be useful for the FFT in our MPC. (Closes#16)
If we're happy with depth 29 (over 268 million possible joinsplits), this will probably be the final change to the constraint system before 1.0.
The partition checking code was using chainActive timestamps
to detect partitioning; with headers-first syncing, it should use
(and with this pull request, does use) pIndexBestHeader timestamps.
Fixes issue #6251
Github-Pull: #6256
Rebased-From: 65b94545036ae6e38e79e9c7166a3ba1ddb83f66
Make it possible to opt-out of the centralized alert system by providing
an option `-noalerts` or `-alerts=0`. The default remains unchanged.
This is a gentler form of #6260, in which I went a bit overboard by
removing the alert system completely.
I intend to add this to the GUI options in another pull after this.
Github-Pull: #6274
Rebased-From: 02a6702a82a5b00e0e0351041dd3267308b7f319
In some corner cases, it may be possible for recent blocks to end up in
the same block file as much older blocks. Previously, the pruning code
would stop looking for files to remove upon first encountering a file
containing a block that cannot be pruned, now it will keep looking for
candidate files until the target is met and all other criteria are
satisfied.
This can result in a noncontiguous set of block files (by number) on
disk, which is fine except for during some reindex corner cases, so
make reindex preparation smarter such that we keep the data we can
actually use and throw away the rest. This allows pruning to work
correctly while downloading any blocks needed during the reindex.
Rebased-From: c257a8c9a6397eee40734b235a4fdcb8045aec91
Github-Pull: #6221
To protect privacy, do not use UPNP when a proxy is set. The user may
still specify -listen=1 to listen locally (for a hidden service), so
don't rely on this happening through -listen.
Fixes#2927.
86a5f4b Relocate calls to CheckDiskSpace (Alex Morcos)
67708ac Write block index more frequently than cache flushes (Pieter Wuille)
b3ed423 Cache tweak and logging improvements (Pieter Wuille)
fc684ad Use accurate memory for flushing decisions (Pieter Wuille)
046392d Keep track of memory usage in CCoinsViewCache (Pieter Wuille)
540629c Add memusage.h (Pieter Wuille)
Create a monitoring task that counts how many blocks have been found in the last four hours.
If very few or too many have been found, an alert is triggered.
"Very few" and "too many" are set based on a false positive rate of once every fifty years of constant running with constant hashing power, which works out to getting 5 or fewer or 48 or more blocks in four hours (instead of the average of 24).
Only one alert per day is triggered, so if you get disconnected from the network (or are being Sybil'ed) -alertnotify will be triggered after 3.5 hours but you won't get another -alertnotify for 24 hours.
Tested with a new unit test and by running on the main network with -debug=partitioncheck
Run test/test_bitcoin --log_level=message to see the alert messages:
WARNING: check your network connection, 3 blocks received in the last 4 hours (24 expected)
WARNING: abnormally high number of blocks generated, 60 blocks received in the last 4 hours (24 expected)
The -debug=partitioncheck debug.log messages look like:
ThreadPartitionCheck : Found 22 blocks in the last 4 hours
ThreadPartitionCheck : likelihood: 0.0777702
a8cdaf5 checkpoints: move the checkpoints enable boolean into main (Cory Fields)
11982d3 checkpoints: Decouple checkpoints from Params (Cory Fields)
6996823 checkpoints: make checkpoints a member of CChainParams (Cory Fields)
9f13a10 checkpoints: store mapCheckpoints in CCheckpointData rather than a pointer (Cory Fields)
Connecting the chain can take quite a while.
All the while it is still showing `Loading wallet...`.
Add an init message to inform the user what is happening.
libsecp256k1's API changed, so update key.cpp to use it.
Libsecp256k1 now has explicit context objects, which makes it completely thread-safe.
In turn, keep an explicit context object in key.cpp, which is explicitly initialized
destroyed. This is not really pretty now, but it's more efficient than the static
initialized object in key.cpp (which made for example bitcoin-tx slow, as for most of
its calls, libsecp256k1 wasn't actually needed).
This also brings in the new blinding support in libsecp256k1. By passing in a random
seed, temporary variables during the elliptic curve computations are altered, in such
a way that if an attacker does not know the blind, observing the internal operations
leaks less information about the keys used. This was implemented by Greg Maxwell.
This adds a -prune=N option to bitcoind, which if set to N>0 will enable block
file pruning. When pruning is enabled, block and undo files will be deleted to
try to keep total space used by those files to below the prune target (N, in
MB) specified by the user, subject to some constraints:
- The last 288 blocks on the main chain are always kept (MIN_BLOCKS_TO_KEEP),
- N must be at least 550MB (chosen as a value for the target that could
reasonably be met, with some assumptions about block sizes, orphan rates,
etc; see comment in main.h),
- No blocks are pruned until chainActive is at least 100,000 blocks long (on
mainnet; defined separately for mainnet, testnet, and regtest in chainparams
as nPruneAfterHeight).
This unsets NODE_NETWORK if pruning is enabled.
Also included is an RPC test for pruning (pruning.py).
Thanks to @rdponticelli for earlier work on this feature; this is based in
part off that work.
According to Tor's extensions to the SOCKS protocol
(https://gitweb.torproject.org/torspec.git/tree/socks-extensions.txt)
it is possible to perform stream isolation by providing authentication
to the proxy. Each set of credentials will create a new circuit,
which makes it harder to correlate connections.
This patch adds an option, `-proxyrandomize` (on by default) that randomizes
credentials for every outgoing connection, thus creating a new circuit.
2015-03-16 15:29:59 SOCKS5 Sending proxy authentication 3842137544:3256031132
zkbot
Jack Grigg
lpescher
Simon
Sean Bowe
ITH4Coinomia
Pieter Wuille
Chirag Davé
Daira Hopwood
Taylor Hornby
Patrick Strateman
aniemerg
Alex Morcos
Adam Weiss
Wladimir J. van der Laan
Gavin Andresen
Luke Dashjr
jtimon
Philip Kaufmann
Jonas Schnelli
Corinne Dashjr
Cory Fields
mrbandrews
Michael Ford