`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.
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.
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.
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
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.