* Implementation of `hash_to_field` as defined in the standard
* Implementation of `hash_to_curve` as defined in the standard, by changing the mechanism over which we chose the sign.
* For the point above, had to change the `elligator_encode` to return whether `eps` is a square or not (required for `hash_to_curve`).
* Included test vectors of the draft.
* Included `FieldElement::from_bytes_wide(bytes: &u8; 64])` to reduce integers encoded in 64 bytes.
* curve: rename `FieldElement*::as_bytes` => `::to_bytes`
Methods named `as_*` should perform a zero-cost borrowing conversion:
https://rust-lang.github.io/api-guidelines/naming.html#ad-hoc-conversions-follow-as_-to_-into_-conventions-c-conv
Methods named `to_*` can perform an expensive owned conversion.
Since the `FieldElement*` types are technically part of the public API
(but feature gated), this also preserves the old names with a
deprecation. We can remove them in the next breaking release.
The same change was also made to the backend `Scalar*` types, however
these types are not a part of the public API.
Adds a lints section to the top of lib.rs with the following:
#![warn(
clippy::unwrap_used,
missing_docs,
rust_2018_idioms,
unused_lifetimes,
unused_qualifications
)]
`warn` is used instead of `deny` to prevent the lints from firing during
local development, however we already configure `-D warnings` in CI so
if any lint fails on checked-in code, it will cause a CI failure.
This commit also fixes or explicitly allows any current violations of
these lints. The main ones were:
- `clippy::unwrap_used`: replaces usages of `unwrap` with `expect`
- `rust_2018_idioms`: no implicit lifetimes, which were present on
usages of `core::fmt::Formatter`
