Bernstein-Yang cleanups; MSRV 1.73 (#437)

Refactors the `CInt` type into `Uint62L` which always uses a 62-bit
unsaturated representation. This is mostly to reduce the overall number
of const generic parameters involved, since Bernstein-Yang always uses a
62-bit unsaturated representation (at least as currently implemented).

Moves the `S` parameter from `invert` into the `BernsteinYangInverter`
struct itself. This allows the type to always "know" its associated
inverter, rather than leaving it up to the end user to calculate.

Also changes the `invert` method to accept a `Uint` as input.

Bumps MSRV to 1.73 since it uses the `int_roundings` feature to compute
the number of unsaturated limbs from the number of saturated limbs.

Author: tarcieri

.github/workflows/crypto-bigint.yml

@@ -20,7 +20,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.70.0 # MSRV
+          - 1.73.0 # MSRV
           - stable
         target:
           - thumbv7em-none-eabi
@@ -48,15 +48,15 @@ jobs:
         include:
           # 32-bit Linux
           - target: i686-unknown-linux-gnu
-            rust: 1.70.0 # MSRV
+            rust: 1.73.0 # MSRV
             deps: sudo apt update && sudo apt install gcc-multilib
           - target: i686-unknown-linux-gnu
             rust: stable
             deps: sudo apt update && sudo apt install gcc-multilib
 
           # 64-bit Linux
           - target: x86_64-unknown-linux-gnu
-            rust: 1.70.0 # MSRV
+            rust: 1.73.0 # MSRV
           - target: x86_64-unknown-linux-gnu
             rust: stable
     steps:
@@ -126,7 +126,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: 1.72.0
+          toolchain: 1.73.0
           components: clippy
       - run: cargo clippy --all --all-features -- -D warnings
 
@@ -146,7 +146,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: 1.70.0
+          toolchain: 1.73.0
       - run: cargo build --benches
       - run: cargo build --all-features --benches
 

Cargo.toml

@@ -14,7 +14,7 @@ keywords = ["arbitrary", "crypto", "bignum", "integer", "precision"]
 readme = "README.md"
 resolver = "2"
 edition = "2021"
-rust-version = "1.70"
+rust-version = "1.73"
 
 [dependencies]
 subtle = { version = "2.5", default-features = false }

README.md

@@ -39,7 +39,7 @@ microcontrollers).
 
 ## Minimum Supported Rust Version
 
-This crate requires **Rust 1.70** at a minimum.
+This crate requires **Rust 1.73** at a minimum.
 
 We may change the MSRV in the future, but it will be accompanied by a minor
 version bump.
@@ -68,7 +68,7 @@ dual licensed as above, without any additional terms or conditions.
 [build-image]: https://github.com/RustCrypto/crypto-bigint/actions/workflows/crypto-bigint.yml/badge.svg
 [build-link]: https://github.com/RustCrypto/crypto-bigint/actions/workflows/crypto-bigint.yml
 [license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
-[rustc-image]: https://img.shields.io/badge/rustc-1.70+-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.73+-blue.svg
 [chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg
 [chat-link]: https://rustcrypto.zulipchat.com/#narrow/stream/300602-crypto-bigint