diff --git a/.github/workflows/kdf.yml b/.github/workflows/kdf.yml
new file mode 100644
index 000000000..a76cf9578
--- /dev/null
+++ b/.github/workflows/kdf.yml
@@ -0,0 +1,54 @@
+name: kdf
+
+on:
+ pull_request:
+ paths:
+ - "kdf/**"
+ - "Cargo.*"
+ push:
+ branches: master
+
+defaults:
+ run:
+ working-directory: kdf
+
+env:
+ CARGO_INCREMENTAL: 0
+ RUSTFLAGS: "-Dwarnings"
+
+jobs:
+ build:
+ runs-on: ubuntu-latest
+ strategy:
+ matrix:
+ rust:
+ - 1.85.0 # MSRV
+ - stable
+ target:
+ - thumbv7em-none-eabi
+ - wasm32-unknown-unknown
+ steps:
+ - uses: actions/checkout@v4
+ - uses: RustCrypto/actions/cargo-cache@master
+ - uses: dtolnay/rust-toolchain@master
+ with:
+ toolchain: ${{ matrix.rust }}
+ targets: ${{ matrix.target }}
+ - run: cargo build --no-default-features --release --target ${{ matrix.target }}
+
+ test:
+ runs-on: ubuntu-latest
+ strategy:
+ matrix:
+ rust:
+ - 1.85.0 # MSRV
+ - stable
+ steps:
+ - uses: actions/checkout@v4
+ - uses: RustCrypto/actions/cargo-cache@master
+ - uses: dtolnay/rust-toolchain@master
+ with:
+ toolchain: ${{ matrix.rust }}
+ - run: cargo check --all-features
+ - run: cargo test
+ - run: cargo test --release
diff --git a/Cargo.lock b/Cargo.lock
index 6fd5180be..4f0f2231d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -350,6 +350,10 @@ version = "1.0.15"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
+[[package]]
+name = "kdf"
+version = "0.0.0"
+
[[package]]
name = "keccak"
version = "0.2.0-pre.0"
diff --git a/Cargo.toml b/Cargo.toml
index 51544176c..2020c1440 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,6 +8,7 @@ members = [
"crypto-common",
"digest",
"elliptic-curve",
+ "kdf",
"kem",
"password-hash",
"universal-hash",
diff --git a/kdf/Cargo.toml b/kdf/Cargo.toml
new file mode 100644
index 000000000..6849e1009
--- /dev/null
+++ b/kdf/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "kdf"
+version = "0.0.0"
+authors = ["RustCrypto Developers"]
+edition = "2024"
+rust-version = "1.85"
+documentation = "https://docs.rs/kdf"
+readme = "README.md"
+repository = "https://github.com/RustCrypto/traits"
+license = "Apache-2.0 OR MIT"
+keywords = ["crypto"]
+categories = ["cryptography", "no-std"]
+description = "Traits for Key Derivation Functions"
diff --git a/kdf/LICENSE-APACHE b/kdf/LICENSE-APACHE
new file mode 100644
index 000000000..78173fa2e
--- /dev/null
+++ b/kdf/LICENSE-APACHE
@@ -0,0 +1,201 @@
+ Apache License
+ Version 2.0, January 2004
+ http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
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+5. Submission of Contributions. Unless You explicitly state otherwise,
+ any Contribution intentionally submitted for inclusion in the Work
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+7. Disclaimer of Warranty. Unless required by applicable law or
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+ Contributor provides its Contributions) on an "AS IS" BASIS,
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+8. Limitation of Liability. In no event and under no legal theory,
+ whether in tort (including negligence), contract, or otherwise,
+ unless required by applicable law (such as deliberate and grossly
+ negligent acts) or agreed to in writing, shall any Contributor be
+ liable to You for damages, including any direct, indirect, special,
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+ on Your own behalf and on Your sole responsibility, not on behalf
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+Unless required by applicable law or agreed to in writing, software
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diff --git a/kdf/LICENSE-MIT b/kdf/LICENSE-MIT
new file mode 100644
index 000000000..49dbb9dd8
--- /dev/null
+++ b/kdf/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2025 RustCrypto Developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/kdf/README.md b/kdf/README.md
new file mode 100644
index 000000000..9e30f6d42
--- /dev/null
+++ b/kdf/README.md
@@ -0,0 +1,40 @@
+# [RustCrypto]: Key Derivation Functions (KDFs)
+
+[![crate][crate-image]][crate-link]
+[![Docs][docs-image]][docs-link]
+[![Build Status][build-image]][build-link]
+![Apache2/MIT licensed][license-image]
+![Rust Version][rustc-image]
+[![Project Chat][chat-image]][chat-link]
+
+## License
+
+Licensed under either of
+
+ * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
+ * [MIT license](http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.
+
+[//]: # (badges)
+
+[crate-image]: https://img.shields.io/crates/v/kdf.svg
+[crate-link]: https://crates.io/crates/kdf
+[docs-image]: https://docs.rs/kdf/badge.svg
+[docs-link]: https://docs.rs/kdf/
+[license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.85+-blue.svg
+[chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg
+[chat-link]: https://rustcrypto.zulipchat.com/#narrow/channel/260043-KDFs
+[build-image]: https://github.com/RustCrypto/traits/actions/workflows/kdf.yml/badge.svg?branch=master
+[build-link]: https://github.com/RustCrypto/traits/actions/workflows/kdf.yml?query=branch:master
+
+[//]: # (links)
+
+[RustCrypto]: https://github.com/RustCrypto
diff --git a/kdf/src/lib.rs b/kdf/src/lib.rs
new file mode 100644
index 000000000..c9e8223c5
--- /dev/null
+++ b/kdf/src/lib.rs
@@ -0,0 +1,16 @@
+#![doc = include_str!("../README.md")]
+#![no_std]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+#![doc(
+ html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
+ html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg"
+)]
+#![forbid(unsafe_code)]
+#![warn(missing_docs, unused_qualifications, missing_debug_implementations)]
+
+/// Use the KDF to derive the given amount of output.
+pub trait Derive {
+ /// Consumes the KDF instance and derives as much data as will fit in `out`,
+ /// overwriting its contents.
+ fn derive(self, out: &mut [u8]);
+}