ctutils v0.1.0 (#1265)

Initial release

Author: tarcieri

Cargo.lock

@@ -3,3 +3,6 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## 0.1.0 (2025-12-19)
+- Initial release

ctutils/CHANGELOG.md

@@ -5,7 +5,7 @@ Constant-time utility library with selection and equality testing support target
 applications. Supports `const fn` where appropriate. Built on the `cmov` crate which provides
 architecture-specific predication intrinsics. Heavily inspired by the `subtle` crate.
 """
-version = "0.0.0"
+version = "0.1.0"
 authors = ["RustCrypto Developers"]
 license = "Apache-2.0 OR MIT"
 homepage = "https://github.com/RustCrypto/utils/tree/master/ctselect"
@@ -21,3 +21,6 @@ cmov = "0.4"
 
 # optional dependencies
 subtle = { version = "2", optional = true, default-features = false }
+
+[package.metadata.docs.rs]
+all-features = true

ctutils/Cargo.toml

@@ -8,7 +8,7 @@
 
 Constant-time utility library with selection and equality testing support targeting cryptographic
 applications. Supports `const fn` where appropriate. Built on the [`cmov`] crate which provides
-architecture-specific predication intrinsics. Heavily inspired by the `subtle` crate.
+architecture-specific predication intrinsics. Heavily inspired by the [`subtle`] crate.
 
 ## About
 
@@ -65,3 +65,4 @@ dual licensed as above, without any additional terms or conditions.
 
 [RustCrypto]: https://github.com/RustCrypto
 [`cmov`]: https://docs.rs/cmov
+[`subtle`]: https://docs.rs/subtle

ctutils/README.md

@@ -13,10 +13,10 @@ use core::ops::{BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign,
 pub struct Choice(u8);
 
 impl Choice {
-    /// The falsy value.
+    /// Equivalent of [`false`].
     pub const FALSE: Self = Self(0);
 
-    /// The truthy value.
+    /// Equivalent of [`true`].
     pub const TRUE: Self = Self(1);
 
     /// Create a new [`Choice`] from the given `u8` value, which should be either `0` or `1`.

ctutils/src/choice.rs

@@ -63,6 +63,17 @@
 //! *NOTE: for `subtle` users, this is the equivalent of the `ConditionallySelectable` trait*
 //!
 //! [predication]: https://en.wikipedia.org/wiki/Predication_(computer_architecture)
+//!
+//! # [`subtle`] interop
+//!
+//! When the `subtle` feature of this crate is enabled, bidirectional [`From`] impls are available
+//! for the following types:
+//!
+//! - [`Choice`] <=> [`subtle::Choice`]
+//! - [`CtOption`] <=> [`subtle::CtOption`]
+//!
+//! This makes it possible to use `ctutils` in a codebase where other dependencies are using
+//! `subtle`.
 
 mod choice;
 mod ct_option;

ctutils/src/lib.rs

@@ -1,7 +1,7 @@
 use crate::Choice;
 use core::cmp;
 
-/// Constant time greater than operation.
+/// Constant time greater than.
 pub trait CtGt {
     /// Compute whether `self > other` in constant time.
     fn ct_gt(&self, other: &Self) -> Choice;

ctutils/src/traits/ct_gt.rs

@@ -1,7 +1,7 @@
 use crate::Choice;
 use core::cmp;
 
-/// Constant time less than operation.
+/// Constant time less than.
 pub trait CtLt {
     /// Compute whether `self < other` in constant time.
     fn ct_lt(&self, other: &Self) -> Choice;