Add Readme (#4)

Signed-off-by: Jonas Schneider-Bensch <jonas@cryspen.com>

Author: jschneider-bensch

README.md

@@ -1,6 +1,145 @@
 [//]: # (SPDX-License-Identifier: CC-BY-4.0)
-[//]: # (TODO Customize project readme)
 
-# template-code
+# mlkem-rust-libcrux
+`mlkem-rust-libcrux` is a portable Rust implementation of ML-KEM which
+optionally supports optimizations for AVX2 and NEON platforms.
+
+It originates in the `libcrux` library of formally verified
+cryptographic algorithm in Rust.
+
+## Getting Started
+To use this implementation of ML-KEM in your Rust project, run
+
+```
+cargo add libcrux-ml-kem
+```
+in your project directory, or add
+
+```
+libcrux-ml-kem = "0.0.3"
+```
+to your `Cargo.toml`.
+
+
+## Status
+The modules
+- `mlkem512`
+- `mlkem768`
+- `mlkem1024`
+implement the three parameter sets for ML-KEM defined in FIPS 203. 
+
+Each module provides the following API:
+- `generate_key_pair`: to generate an ML-KEM key pair,
+- `encapsulate`: to encapsulate a shared secret towards a given ML-KEM public key,
+- `decapsulate`: to decapsulate a shared secret from a ciphertext using an ML-KEM private key,
+- `validate_public_key`: to perform validation of public keys as required by FIPS 203 prior to encapsulation,
+- `validate_private_key`: to perform validation of private keys and ciphertexts as required by FIPS 203 prior to decapsulation.
+
+For detailed documentation, please refer to
+[docs.rs](https://docs.rs/libcrux-ml-kem/latest/libcrux_ml_kem/).
+
+### Portable and Optimized Implementations
+The crate provides portable, as well as AVX2- and NEON-optimized
+implementations of the above API. By defautl, the crate's `build.rs`
+will include the portable implementation and one of the optimized
+implementations in the build, according to the value of
+`CARGO_CFG_TARGET_ARCH`.
+
+In addition, the above functions perform CPU feature detection at
+runtime to ensure the most efficient implementation for the given
+platform is selected.
+
+It is recommended to rely on the automatic feature detection, but specific
+builds can be forced by setting environment variables,
+`LIBCRUX_ENABLE_SIMD128=1` or `LIBCRUX_ENABLE_SIMD256=1`.
+
+### Unpacked APIs
+The default KEM API described above operates on serialized keys,
+i.e. `encapsulate` will take a serialized ML-KEM public key as input
+and `decapsulate` will take a serialized ML-KEM private key as input,
+and these must be validated before use with `validate_public_key`
+and `validate_private_key` for FIPS 203 compliance.
+
+In addition, in each parameter set module, (e.g. `mlkem768`) the crate
+provides an API for working with "unpacked" keys, which have already
+been deserialized. For some applications it may thus be advantageous
+to validate key material once, then deserialized into unpacked
+representation once, and to use the the already validated and
+deserialized form from then on.
+
+The unpacked APIs are platform dependent, so they can be found in
+submodules `mlkem768::portable::unpacked`, `mlkem768::avx2::unpacked`,
+`mlkem768::neon::unpacked`, depending on which of these platform
+specific modules are part of the build in question.
+
+### Common APIs
+The implementation of common APIs across PQCP implementations is
+work-in-progress. Progress for this implementation is tracked in issue
+[`cryspen/libcrux#894`](https://github.com/cryspen/libcrux/issues/894).
+
+### Crate Features
+The crate provides the following features.
+
+Default features:
+- `mlkem512`, `mlkem768` & `mlkem1024`: These can be used to select
+  individual parameter sets. By default, all parameter sets are
+  included.
+- `rand`: Whereas the default APIs for `generate_key_pair` and
+  `encapsulate` expect external provision of random bytes, this
+  feature enables randomized versions of these APIs (in submodules
+  `mlkem512::rand`, `mlkem768::rand`, `mlkem1024::rand`) which take an
+  `&mut impl rand_core::CryptoRng` argument to generate the required
+  randomness internally.
+- `default-no-std` & `std`: Disabling default feature `std` provides
+  `no_std` support. For convenience `default-no-std` collects all default
+  features except `std`.
+  
+Additional features:
+- `kyber`: Provides access to an, as yet, unverified implementation of
+  Kyber as submitted in Round 3 of the NIST PQ competition. The Kyber
+  APIs follow the general structure of the ML-KEM APIs.
+- `check-secret-independence`: All operations on ring elements in the
+  portable implementation use the integer types of the
+  [`libcrux-secrets`](https://crates.io/crates/libcrux-secrets) crate under the hood. That crate allows checking a
+  program operating on these types for secret independence at compile
+  time. Enabling the `check-secret-independence` feature switches on
+  this compile-time checking of secret independence. By default, the
+  integer types of `libcrux-secrets` transparently fall back on Rust's
+  standard integer types.
+- `simd128`, `simd256`: These features force a compilation for NEON or
+  AVX2 targets, respectively, as discussed above.
+- `incremental`: An experimental API, which allows for incremental
+  encapsulation.
+
+## Security
+As outlined in the description of the `check-secret-independence`
+feature above, we leverage the Rust type system to ensure that secret
+values are not used in operations that are known to have
+data-dependent execution time. While the implementation of constant time
+operations is best-effort, as there are no guarantees from the
+compiler, we follow established constant-time patterns and validate
+constant-time code via inspection of the generated assembly
+instructions.
+
+## Verification Status
+The portable and AVX2 code for field arithmetic, NTT polynomial
+arithmetic, serialization, and the generic code for high-level
+algorithms is formally verified using [hax](https://hax.cryspen.com) and [F*](https://fstar-lang.org).
+
+Please refer to [this
+file](https://github.com/cryspen/libcrux/blob/f9d1802c06ffe1dec900367e12b00edb1e7f9963/libcrux-ml-kem/proofs/verification_status.md)
+in the `libcrux-ml-kem` repository for details on the verification of
+this crate.
+
+## Performance
+We provide a dashboard of benchmark results for the main key
+generation, encapsulation and decapsulation APIs across different
+platforms and operating systems at
+[libcrux.cryspen.com](https://libcrux.cryspen.com).
+
+If you wish to run the benchmarks yourself, you can do so by running
+```
+cargo bench
+```
+from the crate root of the `libcrux-ml-kem` crate.
 
-Template for creating code repositories, with basic file setup included