This forward-ports the new Taproot sighash but does not fix a couple
22-blocked TODOs related to the MissingDataBehavior enum. Should be fixed
in a followup commit.
One nontrivial change I had to make was feeding the genesis hash to SignTransaction
(the "global" one in script/sign.cpp) so that it could correctly compute
the sighash at signing time.
This introduces Taproot wallet support. I fixed all the merge conflicts
and ensured that the tests pass, but this is still using the old sighash
(before Russell/Sanket/I redid it) so is not actually production ready.
Will be fixed when we bring Elements #1002 in.
Does the bare minimum to introduce Taproot wallet support with CT; just
adds a CPubKey blinding_pubkey to the taproot destination variant and
updates some visitors.
In future when we define blech32 we will need to make sure we are using
that encoding and using the pubkey.
f9e37f33ce doc: IsFinalTx comment about nSequence & OP_CLTV (Yuval Kogman)
Pull request description:
It's somewhat surprising that a transaction's `nLockTime` field is ignored
when all `nSequence` fields are final, so this change aims to clarify this
behavior and cross reference relevant details of `OP_CHECKLOCKTIMEVERIFY`.
ACKs for top commit:
MarcoFalke:
ACK f9e37f33ce
Tree-SHA512: 88460dacbe4b8115fb1948715f09b21d4f34ba1da9e88d52f0b774a969f845e9eddc5940e7fee66eacdd3062dc40d6d44c3f282b0e5144411fd47eb2320b44f5
At verification time, the to be precomputed data can be inferred from
the transaction itself. For signing, the necessary witnesses don't
exist yet, so just permit precomputing everything in that case.
That results in a much safer interface (making the tweak commit
to the key implicitly using a fixed tag means it can't be used for
unrelated tweaking).
We were previously ruling out 17-20 pubkeys multisig, while they are
only invalid under P2SH context.
This makes multisigs with up to 20 keys be detected as valid by the
solver. This is however *not* a policy change as it would only apply
to bare multisigs, which are already limited to 3 pubkeys.
Note that this does not change the sigOpCount calculation (as it would
break consensus). Therefore 1-16 keys multisigs are counted as 1-16 sigops
and 17-20 keys multisigs are counted as 20 sigops.
Signed-off-by: Antoine Poinsot <darosior@protonmail.com>
It's somewhat surprising that a transaction's nLockTime field is ignored
when all nSequence fields are final, so this change aims to clarify this
behavior and cross reference relevant details of OP_CHECKLOCKTIMEVERIFY.
Several conflicts in the C++ code related to the new `flags` parameter
to `CheckSignature` and the corresponding function being renamed upstream
to `CheckSignatureECDSA`.
Several conflicts in the test harness as Steven sorta pulled the new
upstream ECKey module into the Python code, and the actual upstream
code was slightly different. Also needed to update the feature_taproot
code to always use the non-RANGEPROOF sighash since dynafed is not
enabled in the Taproot test.
Also had to pull the `set_wif` method out of `ECKey` and inline it because
otherwise it triggers a "circular inclusion" error between script.py (which
would pull in `base58_to_bytes` from address.py) and address.py (which now
pulls in some taproot EC related stuff from script.py).
Noticed that #960 does not test the "sighash rangeproof flag set but no
witnesses" case.
Historically lack of amount data has been treated as amount==-1. Change
this and treat it as missing data, as introduced in the previous commits.
To be minimally invasive, do this at SignatureHash() call sites rather
than inside SignatureHash() (which currently has no means or returning
a failure code).
This allows specifying how *TransactionSignatureChecker will behave when
presented with missing transaction data such as amounts spent, BIP341 data,
or spent outputs.
As all call sites still (implicitly) use MissingDataBehavior::ASSERT_FAIL,
this commit introduces no change in behavior.
Moved GetOnlinePakKey to the scriptpubkey manager; the other blinding
stuff remains in the CWallet. At some point after the rebase we should
consider whether there's a better separation to be had between the PAK
related stuff now that we have wallet boxes.
This adds a new `SigVersion::TAPSCRIPT`, makes the necessary interpreter
changes to make it implement BIP342, and uses them for leaf version 0xc0
in Taproot script path spends.
This includes key path spending and script path spending, but not the
Tapscript execution implementation (leaf 0xc0 remains unemcumbered in
this commit).
Includes constants for various aspects of the consensus rules suggested
by Jeremy Rubin.
