Since we are required to check for uniqueness of decoy picks within any given
ring, and since some decoy picks may fail due to unlock time or malformed EC points,
the wallet2 decoy selection code was building up a larger than needed *unique* set of
decoys for each ring according to a certain distribution *without replacement*. After
filtering out the outputs that it couldn't use, it chooses from the remaining decoys
uniformly random *without replacement*.
The problem with this is that the picks later in the picking process are not independent
from the picks earlier in the picking process, and the later picks do not follow the
intended decoy distribution as closely as the earlier picks. To understand this
intuitively, imagine that you have 1023 marbles. You label 512 marbles with the letter A,
label 256 with the letter B, so on and so forth, finally labelling one marble with the
letter J. You put them all into a bag, shake it well, and pick 8 marbles from the bag,
but everytime you pick a marble of a certain letter, you remove all the other marbles
from that bag with the same letter. That very first pick, the odds of picking a certain
marble are exactly how you would expect: you are twice as likely to pick A as you are B,
twice as likely to pick B as you are C, etc. However, on the second pick, the odds of
getting the first pick are 0%, and the chances for everything else is higher. As you go
down the line, your picked marbles will have letters that are increasingly more unlikely
to pick if you hadn't remove the other marbles. In other words, the distribution of the
later marbles will be more "skewed" in comparison to your original distribution of marbles.
In Monero's decoy selection, this same statistical effect applies. It is not as dramatic
since the distribution is not so steep, and we have more unique values to choose from,
but the effect *is* measureable. Because of the protocol rules, we cannot have duplicate
ring members, so unless that restriction is removed, we will never have perfectly
independent picking. However, since the earlier picks are less affected by this
statistical effect, the workaround that this commit offers is to store the order that
the outputs were picked and commit to this order after fetching output information over RPC.
bb33daa add a test for the long term weight cache (Boog900)
65839b5 Fix: long term block weight cache The long term block weight cache was doing a wrong calculation when adding a new block to the cache. (Boog900)
- passphrase logic: remove backward compatibility for 2.4.3, code cleanup.
- fix LibUSB cmake for static builds on OSX
- tests: all tests now work with passphrase logic enabled. Passphrase test added with different passphrase. no_passphrase test added, Trezor pin test added. Testing wallet opening with correct and incorrect passphrase. Trezor test chain revamp, cleanup. Smaller chain, chain file versioning added.
- tests: Trezor tests support TEST_MINING_ENABLED, TEST_MINING_TIMEOUT env vars to change mining-related tests behaviour.
- requires protobuf@21 on osx for now (c++14), building with unlinked protobuf: `CMAKE_PREFIX_PATH=$(find /opt/homebrew/Cellar/protobuf@21 -maxdepth 1 -type d -name "21.*" -print -quit) \
make debug-test-trezor -j8`
- fix tx create from sources, input locking. Originally, creating a synthetic transactions with chaingen could create a transaction with outputs that are still locked in the current block, thus failing chain validation by the daemon. Simple unlock check was added. Some buggy tests were fixed as well as new unlock-checking version of tx creation rejected those, fixes are simple - mostly using correct block after a rewind to construct a transaction
The Monero GUI code was calling `Monero::wallet::setPassword()` on every open/close for some reason,
and the old `store_to()` code called `store_keys()` with `watch_only=false`, even for watch-only wallets.
This caused a bug where the watch-only keys file got saved with with the JSON field `watch_only` set to 0,
and after saving a watch-only wallet once, a user could never open it back up against because `load()` errored out.
This never got brought up before this because you would have to change the file location of the watch-only
wallet to see this bug, and I guess that didn't happen often, but calling the new `store_to()` function with the
new `force_rewrite` parameter set to `true` triggers key restoring and the bug appeared.
