f08276adfc Add convenience methods for keys (Tobin Harding)
b4c7fa0d4e Let the compiler work out int size (Tobin Harding)
c612130864 Borrow secret key (Tobin Harding)
Pull request description:
We have a bunch of `from_<key>` methods for converting between key types. To make the API more ergonomic to use we can add methods that do the same but called on a variable e.g., once applied the following are equivalent:
- `let pk = PublicKey::from_keypair(kp)`
- `let pk = kp.public_key()`
Do this for `SecretKey`, `PublicKey`, `KeyPair`, and `XOnlyKeyPair`.
Fixes: #428
### Note to reviewers
- `XOnlyPublicKey` -> `PublicKey` logic is made up by me, I could not work out how to get `libsecp256k1` to do this.
- Please review the tests carefully, they include assumptions based on my current understanding of the cryptography :)
ACKs for top commit:
sanket1729:
ACK f08276adfc. Thanks for going through all the iterations.
apoelstra:
ACK f08276adfc
Tree-SHA512: 1503a6e570a3958110c6f24cd6d075fe5694b3b32b91a7a9d332c63aa0806198ff10bdd95e7f9de0cf73cbf4e3655c6826bd04e5044d1b019f551471b187c8ea
676a9800df Remove unnecessary panic message (sanket1729)
aa50cc6ced Remove Schnorr word from keypairs (sanket1729)
Pull request description:
Keypairs are pair of EC points that don't have anything to do with the
signature algorithm
ACKs for top commit:
apoelstra:
ACK 676a9800df
tcharding:
ACK 676a9800df
Tree-SHA512: ed3e6f5e821d18641234b308b130271dcd2ec0dd6519a0e9d91564ab8e902b82180d7df377f2bcf08cd3ca1df7ce775422e4a3c386637eaff348e58b033de3ea
We have a bunch of `from_<key>` methods for converting between key types.
To improve the API and make it more ergonomic to use we can add methods
that do the same but can be called on the initial key instead of on the
resulting key's type. E.g. once applied the following are equivalent:
- `let pk = PublicKey::from_keypair(kp)`
- `let pk = kp.public_key()`
Do this for `SecretKey`, `PublicKey`, `KeyPair`, and `XOnlyKeyPair`.
We have two places in the code where we pass a mutable parity integer
to ffi code. At one callsite we tell the compiler explicitly what type
it is (`::secp256k1_sys::types::c_int`) and at the other call site we
let the compiler figure out the type.
Is one way better than the other? I don't know. But letting the compiler
figure it out seems to make the code easier to read.
`SecretKey` implements `Copy` and it is fine to take owneship of it; we
have multiple methods called `from_secret_key` and they all borrow the
secret key parameter. Favour consistency over perfection.
Borrow secret key parameter as is done in other `from_secret_key`
methods.
As we do for other keys implement serde de/serialization for the
`SharedSecret`. Includes implementation of `from_slice` method that is
the borrowed version of `from_bytes` as well as a `FromStr`
implementation that parses a hex string.
Recently we moved from using the identifier 'schnorrsig' to 'schnorr',
we omitted to update the tests.
While we are at it use more idiomatic Rust unit test names (i.e., do not
start test name with `test_` because it stutters when the name is read
in output of `cargo test`).
Recently we moved from using the identifier 'schnorrsig' to 'schnorr',
we omitted to update the schnorr signature size constant.
Deprecate `SCHNORRSIG_SIGNATURE_SIZE` and add
`SCHONORR_SIGNATURE_SIZE`.
Recently we moved from using the identifier 'schnorrsig' to 'schnorr',
we omitted to update the schnorr public key size constant.
Deprecate `SCHNORRSIG_PUBLIC_KEY_SIZE` and add
`SCHONORR_PUBLIC_KEY_SIZE`.
5acf6d23d3 `Parity` conversion and error handling cleanup (Martin Habovstiak)
Pull request description:
This removes the deprecated `From` conversion, replaces it with
`TryFrom`, and adds more convenience conversions. A new error type is
created for the invalid parity error with conversion to catch-all
`Error`.
This is intended for an API-breaking version.
ACKs for top commit:
apoelstra:
ACK 5acf6d23d3
Tree-SHA512: 49b73fc90455c172012b46f36eafa7d256b940f4b431b4eedb577ab07d9402eae40af931e00b3c409bbe502dbcac064a742e874a5e8bedd8d0cbe92a468ae4f6
Currently printing the `SharedSecret` using `Display` or `Debug` prints
the real secret, this is sub-optimal. We have a solution for other
secrets in the project where printing is obfuscated and we provide a
`display_secret` method for explicitly printing.
Mirror the logic for other secrets and obfuscate the `SharedSecret` when printing.
Improve rustdocs on `display_secret` by doing:
- Minor improvements to the rustdocs to aid readability in the editor.
- Do not guarantee (`assert_eq!`) debug output
The `serialize_secret` method is a getter method, it does not do any
serialisation. However we use the method on secret keys and key types so
in order for the name to be uniform use the descriptive name
`secret_bytes`.
Rename `serialize_secret` to be `secret_bytes`.
The identifier `i` is predominantly used for indexing an array but we
are using it as a place holder for the iterated value of an array that
is then printed. The identifier `byte` is more descriptive.
Done in preparation for adding similar code to the `ecdh` module.
In array initialisation we use magic number 64, this is the secret bytes
length multiplied by 2.
Please note; we still use the magic number 32, left as such because it
is used in various ways and its not immediately clear that using a
single const would be any more descriptive.
Use `SECRET_KEY_SIZE * 2` instead of magic number 64.
Hashing the debug output for secrets can be done with `bitcoin_hashes`
not just `std`. Mention this in the obfuscated string output when
neither are available.
5603d71ad3 Limit SharedSecret to 32 byte buffer (Tobin Harding)
d5eeb099ad Use more intuitive local var numbering (Tobin Harding)
834f63c26c Separate new_with_hash into public function (Tobin Harding)
Pull request description:
Currently `SharedSecret` provides a way to get a shared secret using SHA256 _as well as_ a way to use a custom hash function to get the shared secret. Internally `SharedSecret` uses a 256 byte buffer, this is a tad wasteful. We would like to keep the current functionality but reduce memory usage.
- Patch 1: Pulls the `new_with_hash` logic out into a standalone public function that just returns the 64 bytes representing the x,y co-ordinates of the computed shared secret point. Callers are then responsible for hashing this point to get the shared secret (idea by @Kixunil, thanks).
- Patch 2: Does trivial refactor
- Patch 3: Uses a 32 byte buffer internally for `SharedSecret`. This is basically a revert of the work @elichai did to add the custom hashing logic. @elichai please holla if you are not happy with me walking all over this code :)
### Note to reviewers
Secret obfuscation is done on top of this in https://github.com/rust-bitcoin/rust-secp256k1/pull/396, they could be reviewed in order if this work is of interest to you.
ACKs for top commit:
apoelstra:
ACK 5603d71ad3
Tree-SHA512: 48982a4a6a700a111e4c1d5d21d62503d34f433d8cb303d11ff018d2f2be2467fa806107018db16b6d0fcc5ff1a0325dd5790c62c47831c7cd2141a1b6f9467d
e6cb588a23 Breaking: changed `Parity` serialization to `u8` (Martin Habovstiak)
Pull request description:
Serializing the value as `u8` is more compact but this is a breaking
change.
`Visitor` was renamed to avoid hungarian notation and maybe allow other
integers in the future.
For next major version, depends on #400
ACKs for top commit:
tcharding:
tACK e6cb588
apoelstra:
ACK e6cb588a23
Tree-SHA512: 1432a2f3c913c3a7eaec5228fd2dd4e8320d828128bec71812cbf56dd8950c969ed22c69867402eb9e820127868d29b291f3374c6e15de0a3ff2341420c4bbab
The `SharedSecret` uses sha256 to hash the secret, this implies the
secret is 32 bytes of data.
Currently we use a buffer of 256 bytes, this is unnecessary.
Change the implementation of `SharedSecret` to use a 32 byte buffer.
In test code we use multiple pub/sec keys. It is more intuitive if the
'secret 1' is generated by the owner of secret key 1.
Refactor only, no logic changes.
In preparation for simplifying the `SharedSecret` internals pull the
`new_with_hash` function logic out into a standalone public function
that provides similar functionality without use of the `SharedSecret`
struct. Function now returns the 64 bytes of data representing a shared
point on the curve, callers are expected to the hash these bytes to get
a shared secret.
We are using `cfg_attr` to instruct the rustdocs build system to
highlight feature requirements for functions, there is no need to
explicitly mention feature requirements in the text.
Recently we fixed a bunch of feature gates to use `rand-std` instead
of `rand` but in doing so did not notice that the same feature gates
were using `alloc` which is meaningless if `std` is enabled.
Feature gate on `std` if we are using `rand-std`.
c73eb2f391 Use 'extra' instead of 'cheap' (Tobin Harding)
c79eb976ca Remove unnecessary explanation (Tobin Harding)
f95e91a6da Use isn't instead of shouldn't (Tobin Harding)
c9e6ca1680 Use rust-bitcoin module doc style (Tobin Harding)
3fa6762437 Add link to referenced commit (Tobin Harding)
f5e68f3ba7 Add ticks around code snippet (Tobin Harding)
d25431c1da Use 3rd person tense for function docs (Tobin Harding)
c3be285c1d Fix size constant docs (Tobin Harding)
5e07e7596b Add period to sentences (Tobin Harding)
269bde042f Remove unnecessary capitalisation (Tobin Harding)
Pull request description:
In a continued effort to find my feet around here, and inspired by issue #128 I've done a codebase wide audit of the docs (primarily just rustdocs but I glanced at `//` docs as well). Each change is in a separate commit so can be removed if resistance is met. (_"resistance is futile"_).
I've based the stylistic decisions on [work done](https://github.com/rust-bitcoin/rust-bitcoin/pull/704) in rust-bitcoin.
I believe the only controversial change is the last (commit: da161c9 Use rust-bitcoin module doc style), please review that one carefully.
ACKs for top commit:
apoelstra:
ACK c73eb2f391
Tree-SHA512: 5ea215de3fd23ca2a4f25d8f8d59a85a299044fe495269c43b621291ea50c58856fa8544e36cc109b7bdb1a7a59bcab8711f30113572ddce4509d3b06ff0d3b6
Serializing the value as `u8` is more compact but this is a breaking
change.
`Visitor` was renamed to avoid hungarian notation and maybe allow other
integers in the future.
705c9cfbc1 Clarified conversions between `Parity` and integers (Martin Habovstiak)
Pull request description:
This was discussed in https://github.com/rust-bitcoin/rust-secp256k1/pull/390#issuecomment-1033018430
ACKs for top commit:
apoelstra:
ACK 705c9cfbc1
Tree-SHA512: 3ba2ec566099c3c6d1c6f830e4959312b818b8766d924e3d995e6b23bd196ab747cc03d46f494ef451569188b0163f53e3236cacd20bfae9118ee76bcdbc9c02
4c43d5e20f Add custom Debug impl for RecoverableSignature (Tobin Harding)
Pull request description:
Currently when debug printing the `RecoverableSignature` we do so byte by byte, this means that the output differs depending on the endianess of the machine. If instead we serialize the signature in compact form then the output is the same irrespective of the endianess.
With this applied the following two commands now pass:
```
cargo test test_debug_output --features=recovery
```
```
cross test --target powerpc-unknown-linux-gnu test_debug_output --features=recovery
```
Fixes: #375
ACKs for top commit:
apoelstra:
ACK 4c43d5e20f
Tree-SHA512: 073c2e0e23ce41a2b35f1b1193b07a755b726bf565d61e6bcb23b6bdaab31ba3591f31aa92230b07f7dfc018de0401eba09a6858dc261e66dacb331355f40d76
3c9dd2fb32 Fix example dependency list (Tobin Harding)
Pull request description:
Example relies on `rand-std` not plain `rand` dependency.
I do not understand why the following command passes without this patch
applied
```
cargo test --no-default-features --features=std,rand,bitcoin_hashes
```
But if we put the same code in a standalone binary it fails as expected?
Since the running of this test is _unusual_ and it is primarily meant as
an entry point example to the library, remove the mention of "alloc"
feature and just depend upon "std".
Fixes: #395
ACKs for top commit:
apoelstra:
ACK 3c9dd2fb32
Tree-SHA512: 8e7ec7ac846e2916c29b74c7485650e5242ae1141c12c69b50d74efdfee71c11a52cd454231d2a7cdd6f8f683d3ba4369f9bf898a6b9351dc92c2a4e2bd626cd
Our API often involves a `Secp256k1` parameter, when users enable the
`global-context` feature they must then pass `SECP256K1` into these
functions. This is kind of clunky since the global is by definition
available everywhere.
Make the API more ergonomic for `global-context` builds by adding
various API functions/methods that use the global context implicitly.
The global context is already in scope in tests since we use a glob
import. No clue why Clippy does not warn for this.
Remove unnecessary import statement in test function.
Recently we introduced uniform styling for module docs over in
`rust-bitcoin` repo. We can do the same here but its a bit controversial
because it removes the heading from module docs and every single public
module in rust-secp256k1 uses a heading. Instead we use a full
sentences. Also makes uniform the trailing `//!`.
As is typical in the Rust ecosystem use the third person tense when
documenting functions. E.g.,
```
/// Creates a new Foo.
```
As opposed to
```
/// Create a new Foo.
```
Example relies on `rand-std` not plain `rand` dependency.
I do not understand why the following command passes without this patch
applied
```
cargo test --no-default-features --features=std,rand,bitcoin_hashes
```
But if we put the same code in a standalone binary it fails as expected?
Since the running of this test is _unusual_ and it is primarily meant as
an entry point example to the library, remove the mention of "alloc"
feature and just depend upon "std".
Currently when debug printing the `RecoverableSignature` we do so byte
by byte, this means that the output differs depending on the endianess
of the machine. If instead we serialize the signature in compact form
then the output is the same irrespective of the endianess.
With this applied the following two commands now pass:
```
cargo test test_debug_output --features=recovery
```
cross test --target powerpc-unknown-linux-gnu test_debug_output --features=recovery
```
Fixes: #375
b3503ba148 Add example to SharedSecret (Tobin Harding)
Pull request description:
Currently the rustdoc on `SharedSecret` is wildly incorrect (possibly a cut'n'pasta error).
Fix the rustdoc for `SharedSecret` and add an examples section to assist testing the public API.
Fixes: #249
ACKs for top commit:
apoelstra:
ACK b3503ba148
Tree-SHA512: 650092388099bb415c11ea335ca6b64c90094f1a51ceecc403911316ee62da0279488af6fa66e00ee5269c129f06d4641085f8ab9be91c98d24a7a4449d235c2
Currently the rustdoc on `SharedSecret` is wildly incorrect (possibly a
cut'n'pasta error).
Fix the rustdoc for `SharedSecret` and add an examples section to assist
testing the public API.
Fixes: 249
Now that we opportunistically randomize the context on creation if
`rand-std` is enabled it would be nice to encourage users who do not
wish to use `rand-std` to randomize the context. We already have an API
to do this but it requires a separate call to do so. Instead of adding a
bunch of additional constructors elect to add documentation to the
current constructors guiding users towards randomization.
We recently implemented opportunistic randomization of the context
object if the the `rand-std` feature is enabled. Both for the global
context and also for signing context constructors.
Add documentation about `rand-std` feature in relation to the context
object.
Instead of providing a mechanism for users to opt out of randomization
we can just feature gate the call site i.e., opportunistically randomize
the global context on creation if `rand-std` feature is enabled.
2732891359 Change rand to rand-std in lib.rs documentation (Vincent Liao)
Pull request description:
I copy-pasted the key-generation example written on the documentation, but it didn't work. It only worked when I used the feature `rand-std` instead of `rand`.
To reproduce, boot up a new Rust project, and add this to main.rs:
```
use secp256k1::rand::rngs::OsRng;
use secp256k1::{Secp256k1, Message};
use secp256k1::hashes::sha256;
let secp = Secp256k1::new();
let mut rng = OsRng::new().expect("OsRng");
let (secret_key, public_key) = secp.generate_keypair(&mut rng);
let message = Message::from_hashed_data::<sha256::Hash>("Hello World!".as_bytes());
let sig = secp.sign_ecdsa(&message, &secret_key);
assert!(secp.verify_ecdsa(&message, &sig, &public_key).is_ok());
```
Using this dependencies causes error: `secp256k1 = {version="0.21.2", features=["rand", "bitcoin_hashes"]}`. After replacing `rand` with `rand-std`, it works.
ACKs for top commit:
apoelstra:
ACK 2732891
tcharding:
tACK 2732891359
Tree-SHA512: 6b5436bc71bab7535e432e119679bc6bcb11d2575b609e039cc25c122ae92b528f95a673e9c643a6cfa2ee3a663f7efdd61731b6084261c52a220448b6f72d12
Seems there is a bug in cargo, the tests in `key.rs` run successfully
but AFAICT they should fail. Here is an example, running `cargo test
--features=rand` should make this test fail but it doesn't?
```
/// Secret 256-bit key used as `x` in an ECDSA signature.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # #[cfg(all(feature = "rand", any(feature = "alloc", feature = "std")))] {
/// use secp256k1::{rand, Secp256k1, SecretKey};
///
/// let secp = Secp256k1::new();
/// let secret_key = SecretKey::new(&mut rand::thread_rng());
/// # }
/// ```
Anywho, use the correct feature gate: `rand-std`.
Various combinations of features trigger lint warnings for unused code,
all warnings are caused by incorrect feature gating.
Correct feature gating to remove Clippy warnings during testing.
Currently various features fail to build when enabled without default
features. This is because many tests need feature gating.
Feature gating the import statements quickly turns into spaghetti when
trying to cover all combinations of two features correctly, instead just
allow unused imports on `tests` modules where needed.
Add correct feature requirements to the examples so they also can be run
without default features.
Improve the CI script by doing:
- Add `std` to the feature matrix.
- Add `--no-default-features` to test runs in the CI script.
The `Debug` implementation for secrets is feature gated on `std` because
it uses a hasher from `std`. If `bitcoin_hashes` is enabled we can use
it for hashing. If neither `std` nor `bitcoin_hashes` is enabled fall
back to outputting:
<secret requires std or bitcoin_hashes feature to display>
Remove the docs conditional since we now implement `Debug` always.
aa828f01a5 Improve documentation in the key module (Tobin Harding)
9e46d6f122 Add examples to types and methods in key module (Tobin Harding)
a7f3d9bcfd Improve key module docs (Tobin Harding)
6d23614467 Improve lib.rs rustdocs (Tobin Harding)
4c4268f1ad Improve docs on method generate_keypair (Tobin Harding)
Pull request description:
This PR is an initial attempt to more thoroughly test our public API.
Add examples to various types/methods/functions in the key module.
I'm not entirely sure when is enough, do we want an example on every single public method, function, and type or is this overkill. In this PR I tried to find a balance by doing ever method/function that took an argument that is a custom type from this lib. I think this should be extended to include return values too though ...
Thanks to @thomaseizinger for the idea!
First 2 patches are docs improvements to `lib.rs`.
ACKs for top commit:
apoelstra:
ACK aa828f01a5
Tree-SHA512: 9383ad263469f98ce7e988d47edc1482a09a0ce82f43d3991bd80aabdf621430f4a3c86be4debf33232dcb1d60d3e81f2c6d930ea7de7aa0e34b037accd7bc98
We recently patched much of the docs in the `key` module, lets attempt
to attain perfection.
Improve docs by doing:
- Use full stops
- Use 100 character column width
- Use plural third person tense
- Use plural for section headings
- Fix any grammar mistakes
- Use code ticks and links as appropriate
Done in an effort to better test our public API.
Add tests in the `Examples` section as is idiomatic in the Rust
ecosystem.
Make other minor improvements to any rusdocs we touch:
- Use full stops
- Use 100 character column width
- Use plural third person tense
- Use plural for section headings
Improve method docs by doing:
- Remove 'batch' comment
- Remove mention of required features, docs already show this
- Use links to types as well as ticks
Recently we made a wee mess with the `Parity` opaque type. Let's fix it
up by doing:
- Use an enum with variants `Even` and `Odd`.
- Add explicit conversion methods to/from u8 and i32
- Implement `BitXor`
Note: This patch is an API breaking change that does _not_ follow the
deprecation guidelines. Rust does not allow deprecating `From` impl
blocks AFAICT.
47411ce73d Fix typo in documentation (Tobin Harding)
Pull request description:
Docs reference a function name but there is a typo.
'grund' -> 'grind'.
ACKs for top commit:
apoelstra:
ACK 47411ce73d
Tree-SHA512: e6724f1c7972625d59be0ae9de358295c9280e2e126e7322d706cbdca342c1189552b2fdeef9370ff4f85ea8ef185ef4447f6693979d5e8548fcfa2df41a491e
Recently we deprecated a bunch of methods/functions. We are still
calling them in test code. Found by Clippy.
Use the shiny new methods/functions instead of the deprecated ones.
We have deprecated all other functions that use the identifier
'schnorrsig' but we missed `generate_schnorrsig_keypair`.
This function is purely a helper function and serves no real purpose
other than to reduce two lines of code to a single line. Downstream
users can write this function themselves if they need it.
Also, we recently added a new public method to `KeyPair` to get the
public key in a slightly more ergonomic fashion. Use `kp.public_key()`
when replacing usage of now deprecated `generate_schnorrsig_keypair`
function.
Currently to get the `XOnlyPublicKey` from a `KeyPair` users must do
`XOnlyPublicKey::from_keypair(&kp)`. While this does the job we can make
the lib more ergonomic by providing a method directly on `KeyPair` that
calls through to `XOnlyPublicKey::from_keypair`.
Add method `KeyPair::public_key(&self)`.
314e8755df Clarify `global-context` feature (Martin Habovstiak)
d52ab85dd5 Added missing features to docs.rs config (Martin Habovstiak)
Pull request description:
Sadly, I missed two details in #353: features missing in docs.rs configuration and `global-context` being a bit confusing.
This PR fixes those, see commit messages for details.
ACKs for top commit:
apoelstra:
ACK 314e8755df
Tree-SHA512: 01bed8ae2f30adcbdd436b514f08a084492d7f4e1a739ca62e6d8b8547e379c01faeda3522733c27ab615acbb4c6cff60e13906cc88a0d2b90e439e7da517466
656f19407b Remove capital letter in middle of docs sentence (Tobin Harding)
Pull request description:
(Candidate for most trivial patch of all time.)
Seems to be a typo, change the 'L' to an 'l'.
ACKs for top commit:
real-or-random:
ACK 656f19407b
Tree-SHA512: 06a4712868c3195a8465b9cf7bd39e55a30e37574086ca27cb032e0109a8fe053411426a15bcb354642bf78e6420b6fa2789ca487c6cc499f741a11220d5dc22
Previously only `global-context-less-secure` was shown in the doc even
though `global-context` may also work. This was strictly correct because
`global-context` implies `global-context-less-secure` which is also
documented but people could miss it or forget about it and then worry
about security or worse, enable less secure feature.
Calling out both fetures seems useful, even important and thankfully
doesn't seem to cause too much noise in the docs.
Currently we have an implementation of `Debug` (also used by `Display`)
for `Signature` that first converts the sig to a `SerializedSignature`
then prints it as hex.
We would like to have an implementation of `Debug` for
`SerializedSignature`, this cannot be derived because of the `data: [u8;
field]`. We can manually implement `Debug` for `SerializedSignature`
exactly as it is currently done for `Signature` and call this new
implementation from `Signature::fmt()`.
This code path is already tested in `lib.rs` in the test function
`signature_display`.
Rustc can warn us when we forget to add `Copy` and `Deubg` trait
implementations to types.
Add lint directives to enable warnings for missing `Copy` and `Debug`
implementations. Use the newly emitted warnings to find types that do
not implement our 'standard' traits. These 'standard' traits are defined
as the set of attributes that it has been found beneficial to
opportunistically add to all types, these are
- Copy
- Clone
- Debug
- PartialEq and Eq
- PartialOrd and Ord
- Hash
e595b39510 Re-export Parity struct (sanket1729)
Pull request description:
pub struct Parity is under a private module key and not re-exported in lib.rs . It is therefore not
possible to use it downstream.
ACKs for top commit:
elichai:
ACK e595b39510
apoelstra:
ACK e595b39510
Tree-SHA512: 2573689f9a08505c8dfe8f79cd921d5a2742a2a2f4f92cf4066fe6557c765c756531d13560fa4fe6461f094b0c11a52aca30b44542eb77eda7dd1ebd24d3b155
18f74d5242 Clarify what does "less security" mean (Martin Habovstiak)
94c55b4d09 Fixed typos/grammar mistakes (Martin Habovštiak)
1bf05523f0 Documented features (Martin Habovstiak)
Pull request description:
This documents the Cargo features making sure docs.rs shows warning for
feature-gated items. They are also explicitly spelled out in the crate
documentation.
The PR is similar in spirit to https://github.com/rust-bitcoin/rust-bitcoin/pull/633
ACKs for top commit:
apoelstra:
ACK 18f74d5242
Tree-SHA512: 8aac3fc5fd8ee887d6b13606d66b3d11ce44662afb92228c4f8da6169e3f70ac6a005b328f427a91d307f8d36d091dcf24bfe4d17dfc034d02b578258719a90a
Andrew Poelstra
Tobin Harding
junderw
sanket1729
Dominik Spicher
Martin Habovstiak
Vincent Liao
elsirion