Make these two functions available to external callers.
CreateBlindValueProof is a wrapper around the static function to avoid
requiring callers to parse things into secp256k1 objects.
It is arguable whether attempting a value proof without an asset
commitment should be treated as incomplete or incorrect blinding. Since
the asset commitment is required to produce the value proof in the first
place, failing to provide it in the source PSET and thus at this call
site is treated as an error.
This does not change the existing behaviour since a missing asset
or value commitment in this function would already cause it to fail.
Future work on the blinding iterface should likely return the blinding
state directly from the verify calls and remove the duplicated mapping of
blinding error codes to transaction blinding error codes, instead of the
verify functions returning just true/false.
Conflicts were mostly obvious, except for those in CreateTransactionInternal.
(This function was moved from wallet.cpp to spend.cpp, and substantially
rewritten, between 0.21 and 22.0.) For those I manually applied the changes
from the diff, which wound up taking a slightly different form.
Also had to update the new test because the `addresses` field of the RPC
output was removed.
a67a2df330 pset: remove one more intermediate-zero check from the blinding logic (Andrew Poelstra)
9eb285c19d test: add test for confidential non-wallet-owned change (Andrew Poelstra)
185d473fe8 walletcreatefundedpsbt: add functional test for blinding edge cases (Andrew Poelstra)
533da12c2c wallet: make sure extra OP_RETURN output is blinded when called from fundraw (Andrew Poelstra)
b09b63bd1b pset: allow input blinding factors to sum to zero, or value to be 0 (Andrew Poelstra)
9afcb83baf wallet: correctly handle blinding of manually-set change addresses (Andrew Poelstra)
9813c3e74a wallet: fix "cannot unblind IsMine output" check in SignPSBT (Andrew Poelstra)
7103471fd5 walletcreatefundedpsbt: signal blinding data correctly to `FundTransaction` (Andrew Poelstra)
Pull request description:
Fixes#1049
Needs backport to 0.21 (and a new rc).
Although there are several bugs here, none affect the functionaries. There is a more thorough summary in the second-to-last commit message.
ACKs for top commit:
achow101:
ACK a67a2df330
Tree-SHA512: 25066c29f080e43cd00c5b33c60a986a8cb5bbf4ca01ceb3b4182c5b8f61979a1d6d946b8f28fa871ec90f44bdb6fc22014b5c11280cf081181db102cd588cdf
There are a number of special cases (and inconsistencies with wallet.cpp)
in the blinding logic that can prevent blinding from succeeding when various
intermediate values are zero. This fixes two of them.
A proper fix would involve adding new APIs to secp-zkp and then overhauling
all of the wallet blinding code. But for now let's get the tests working.
A couple issues with this -- one is that it was verifying the asset
commitment against itself, rather than against the explicit asset,
and the other is that the verification logic had an extra `== 0` at
the end which inverted the verification check.
Both pretty embarassing to have not caught in review..
Instead of not failing and silently allowing bad PSETs to be created,
provide error messages that explain why the operation the user did was
wrong. Specifically for combining PSETs such that they would become
fully blinded but have imbalanced values and blinders, and for blinding
a PSET when the wallet has a blind input but no outputs to blind (would
result in an imbalance).
Surprisingly easy to do. Almost all of the diff resolution was mechanically
* replacing boost::variant with std::variant
* replacing Optional with std::optional
* then replacing `nullopt` with `std::nullopt`
* updating the RPC functions for the new RPCArg::Default type
* update the tests/ directory to make new (since 22) tests use arrays for
createrawtransaction outputs
* other ad-hoc changes to function parameters etc (not too many of these)
I had to "really" change the code in PrecomputePSBTData, which was introduced
in 22.0 and affected by PSET, but this function was like 8 lines long so it
was easy.
Reviewing the diff may be a bit difficult because of the mix of mechanical
changes and ad-hoc things. Probably the most straightforward thing to do
is to redo the merge, `sed -i` to fix the boost::variant and Optional stuff,
then diff the remaining conflicts against this commit.
TODO: grep for `blindpsbt` and you will see that this RPC is still referenced
in documentation and help text even though it was deleted. Need to fix this
in 0.21 in a separate PR.
