The low-S rule for ecdsa signatures is mandated by Bitcoin Core policy/standardness (though not by consensus). If we get signatures from untrusted sources, we should mandate they obey the policy rules. (e.g. from LN peers)
Note that we normalize the signatures in the sig format conversion methods (DER <-> (r,s) <-> sig64).
The BOLTs treat high-S signatures as invalid, and this changes our behaviour to that.
(previously we would silently normalize the S value)
see https://github.com/bitcoin/bitcoin/pull/6769
see https://github.com/lightning/bolts/pull/807
get_preimage_script should really have been private API...
looks like everywhere it is used outside of transaction.py, it is actually abused :/
Other existing usages in plugin code I don't dare to touch without lots of manual testing...
Instead of some functions operating with hex strings,
and others using bytes, this consolidates most things to use bytes.
This mainly focuses on bitcoin.py and transaction.py,
and then adapts the API usages in other files.
Notably,
- scripts,
- pubkeys,
- signatures
should be bytes in almost all places now.
- `bitstring` started depending on `bitarray` in version 4.1 [0]
- that would mean one additional dependency for us (from yet another maintainer), which is not even pure python
- we only use bitstring for bolt11-parsing
- hence this PR rewrites the bolt11-parsing and removes `bitstring` as dependency
- note: I benchmarked lndecode using [1], and the new code performs better,
taking around 80% time needed for old code (when using bitstring 3.1.9, pure python).
Though the variance is quite large in both cases.
[0]: 95ee533ee4/release_notes.txt (L108)
[1]: d7597d96d0
I decided to use the stdlib (hashlib) instead of libsecp for this,
as it is simple enough, and the former is faster on my PC.
Added a unit test that compares the two.
The transaction dict can also contain PSBTs (in addition to complete raw hex txs).
This is the case if the user has saved a partial (e.g. unsigned) tx as local into the history.
fixes https://github.com/spesmilo/electrum/issues/8913
