Makes it possible to compactly provide a delibrately invalid signature
for use with CHECK(MULTI)SIG. For instance with BIP19 if m != n invalid
signatures need to be provided in the scriptSig; prior to this change
those invalid signatures would need to be large DER-encoded signatures.
Note that we may want to further expand on this change in the future by
saying that only OP_0 is a "valid" invalid signature; BIP19 even with
this change is inherently malleable as the invalid signatures can be any
validly encoded DER signature.
on rare occasions, rand() was returning duped values, causing duplicate
transactions.
BuildMerkleTree happily used these, but CPartialMerkleTree caught them and
returned a null merkle root.
Rather than taking changes with rand(), use the loop counter to guarantee
unique values.
At sipa's request, also remove the remaining uses of rand().
Remove initialization from vector (as this is only used in the tests).
Also implement SetHex and GetHex in terms of uint256, to avoid
duplicate code as well as avoid endianness issues (as they
work in term of bytes).
- Methods that access the guts of arith_uint256 are removed,
as these are incompatible between endians. Use uint256 instead
- Serialization is no longer needed as arith_uint256's are never
read or written
- GetHash is never used on arith_uint256
If uint256() constructor takes a string, uint256(0) will become
dangerous when uint256 does not take integers anymore (it will go
through std::string(const char*) making a NULL string, and the explicit
keyword is no help).
SignatureHash and its test function SignatureHashOld
return uint256(1) as a special error signaling value.
Return a local static constant with the same value instead.
This is a check that is mentioned in BIP 37, but never implemented in the
reference code. As Bitcoin Core so far never decodes partial merkle trees,
this is not a problem. But perhaps others use the code as a reference.
OP_CODESEPARATOR is an actual executed instruction, not a declarative
thing, so if it's wrapped in an OP_IF it can be turned off.
Using this to implement Rivest's Paywords is left as an exercise for the
reader.
Although script_valid.json and script_invalid.json are loaded correctly by the
JSON interpreter used by bitcoin core, these same files are often used by other
libraries and do not necessarily load correctly due to the fact that newlines
contained inside strings are not valid and must instead use the escape
character \n. The files tx_valid.json and tx_invalid.json handle this
correctly, so I've changed the formatting in script_valid.json and
script_invalid.json to mirror those files.
Now that signing is deterministic, we can require exact correspondence between the
automatically generated tests and the ones read from JSON. Do this, and update
the tests to those deterministic versions. Note that some flag changes weren't
correctly applied before.
Based on an earlier patch by Peter Todd, though the rules here are different
(P2SH scripts should not have a CLEANSTACK check before the P2SH evaluation).
Add a sanity check to prevent cosmic rays from flipping a bit in the
generated public key, or bugs in the elliptic curve code. This is
simply done by signing a (randomized) message, and verifying the
result.
This turns STRICTENC turn into a softforking-safe change (even though it
is not intended as a consensus rule), and as a result guarantee that using
it for mempool validation only results in consensus-valid transactions in
the mempool.
NOP1 to NOP10 are reserved for future soft-fork upgrades. In the event
of an upgrade such NOPs have *VERIFY behavior, meaning that if their
arguments are not correct the script fails. Discouraging these NOPs by
rejecting transactions containing them from the mempool ensures that
we'll never accept transactions, nor mine blocks, with scripts that are
now invalid according to the majority of hashing power even if we're not
yet upgraded. Previously this wasn't an issue as the IsStandard() rules
didn't allow upgradable NOPs anyway, but 7f3b4e95 relaxed the
IsStandard() rules for P2SH redemptions allowing any redeemScript to be
spent.
We *do* allow upgradable NOPs in scripts so long as they are not
executed. This is harmless as there is no opportunity for the script to
be invalid post-upgrade.
Pieter Wuille