75b49efb3d Implement `Hash` for all array newtypes (elsirion)
Pull request description:
I pondered putting the impl into the array type macro together with `(Partial)Eq`, but that would have meant removing other implementations and potentially implementing it for types where it is not wanted. The drawback of the separate impl is that it is more disconnected from the `(Partial)Eq` impl and could theoretically diverge (although unlikely in case of such a simple type) which would break the trait's contract.
ACKs for top commit:
apoelstra:
ACK 75b49efb3d
Tree-SHA512: 44d1bebdd3437dfd86de8b475f12097c4a2f872905c822a9cde624089fdc20f68f59a7734fdcc6f3a17ed233f70f63258dfd204ca269d2baf8002ffc325ddc87
This reduces the usage of real cryptography in --cfg=fuzzing,
specifically replacing the secret->public key derivation with a
simple copy and ECDH with XOR of the public and private parts
(plus a stream of 1s to make a test pass that expected non-0
output).
It leaves secret tweak addition/multiplication as-is.
It also changes the context creation to over-allocate and store
the context flags at the end of the context buffer, allowing us
to easily test context flags in each function.
While it would be nice to have something fancier (eg XOR-based),
its not immediately obvious how to accomplish this, and better to
fix the issues I have than spend too much time on it.
Fixes#271.
This partially reverts b811ec133a
cc-rs builds C dependencies with reduced visibility to avoid
exporting the C symbols all the way out to any rust-built shared
libraries however we override it with SECP256K1_API. We should
avoid doing this, allowing LTO/DCE to do its work.
We can now run unit tests with the fuzz feature on, and they'll pass,
which is some assurance that fuzzing with the feature on won't lead to
spurious failures due to the fuzz harness inadequately simulating message
signing.
It's super dangerous to use Cargo features for this, since they can be set
accidentally (or maliciously by any crate in a user's entire dep tree). Instead
we can just require users set `RUSTFLAGS` appropriately, which we can easily
do in our fuzzing scripts.
This feature was not useful for Cargo users, since Cargo does not give you
the kind of fine-grained control over C library linkage that you need. So
it was just unnecessarily confusing and would cause the build to break if
you enabled it accidentally, say, with --all-features.
Clippy emits a warning since we define a method that has the same name
as a standard trait. Implement the trait `AsRef` instead of using a
custom method.