hkdf: bump MSRV to 1.81 (#105)

Also remove the `std` crate feature as no longer needed.

.github/workflows/hkdf.yml

@@ -22,7 +22,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.72.0 # MSRV
+          - 1.81.0 # MSRV
           - stable
         target:
           - thumbv7em-none-eabi
@@ -48,7 +48,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - 1.72.0 # MSRV
+          - 1.81.0 # MSRV
           - stable
     steps:
       - uses: actions/checkout@v4

hkdf/CHANGELOG.md

@@ -4,6 +4,14 @@ 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).
 
+## UNRELEASED
+### Breaking changes
+- Removed `std` crate feature ([#105])
+- Bump MSRV to 1.81 ([#105])
+- Bump `hmac` dependency to v0.13
+
+[#105]: https://github.com/RustCrypto/KDFs/pull/105
+
 ## 0.12.3 (2022-02-17)
 ### Fixed
 - Minimal versions build ([#63])

hkdf/Cargo.toml

@@ -10,7 +10,7 @@ keywords = ["crypto", "HKDF", "KDF"]
 categories = ["cryptography", "no-std"]
 readme = "README.md"
 edition = "2021"
-rust-version = "1.72"
+rust-version = "1.81"
 
 [dependencies]
 hmac = "=0.13.0-pre.4"
@@ -21,9 +21,6 @@ hex-literal = "0.4"
 sha1 = { version = "=0.11.0-pre.4", default-features = false }
 sha2 = { version = "=0.11.0-pre.4", default-features = false }
 
-[features]
-std = ["hmac/std"]
-
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]

hkdf/src/errors.rs

@@ -10,9 +10,7 @@ impl fmt::Display for InvalidPrkLength {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-impl ::std::error::Error for InvalidPrkLength {}
+impl core::error::Error for InvalidPrkLength {}
 
 /// Structure for InvalidLength, used for output error handling.
 #[derive(Copy, Clone, Debug)]
@@ -24,6 +22,4 @@ impl fmt::Display for InvalidLength {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
-impl ::std::error::Error for InvalidLength {}
+impl core::error::Error for InvalidLength {}

hkdf/src/lib.rs

@@ -95,9 +95,6 @@
 #![forbid(unsafe_code)]
 #![warn(missing_docs, rust_2018_idioms)]
 
-#[cfg(feature = "std")]
-extern crate std;
-
 pub use hmac;
 
 use core::fmt;