Crate aws_lc_rs

source ·
Expand description

A ring-compatible crypto library using the cryptographic operations provided by AWS-LC. It uses either the auto-generated aws-lc-sys or aws-lc-fips-sys Foreign Function Interface (FFI) crates found in this repository for invoking AWS-LC.


aws-lc-rs is available through It can be added to your project in the standard way using Cargo.toml:

aws-lc-rs = "1.0.0"

Consuming projects will need a C Compiler (Clang or GCC) to build. For some platforms, the build may also require CMake. Building with the “fips” feature on any platform requires CMake and Go.

See our User Guide for guidance on installing build requirements.

§Feature Flags

§alloc (default)

Allows implementation to allocate values of arbitrary size. (The meaning of this feature differs from the “alloc” feature of ring.) Currently, this is required by the io::writer module.

§ring-io (default)

Enable feature to access the io module.

§ring-sig-verify (default)

Enable feature to preserve compatibility with ring’s signature::VerificationAlgorithm::verify function. This adds a requirement on untrusted = "0.7.1".


Enable this feature to have aws-lc-rs use the aws-lc-fips-sys crate for the cryptographic implementations. The aws-lc-fips-sys crate provides bindings to AWS-LC-FIPS 2.x, which has completed FIPS validation testing by an accredited lab and has been submitted to NIST for certification. The static build of AWS-LC-FIPS is used.

Refer to the NIST Cryptographic Module Validation Program’s Modules In Progress List for the latest status of the static or dynamic AWS-LC Cryptographic Module. A complete list of supported operating environments will be made available in the vendor security policy once the validation certificate has been issued. We will also update our release notes and documentation to reflect any changes in FIPS certification status.


Performs an “address sanitizer” build. This can be used to help detect memory leaks. See the “Address Sanitizer” section of the Rust Unstable Book.


Causes aws-lc-sys or aws-lc-fips-sys to generates fresh bindings for AWS-LC instead of using the pre-generated bindings. This feature requires libclang to be installed. See the requirements for rust-bindgen


Although this library attempts to be fully compatible with ring (v0.16.x), there are a few places where our behavior is observably different.

  • Our implementation requires the std library. We currently do not support a #![no_std] build.
  • We can only support a subset of the platforms supported by aws-lc-sys. See the list of supported platforms above.
  • Ed25519KeyPair::from_pkcs8 and Ed25519KeyPair::from_pkcs8_maybe_unchecked both support parsing of v1 or v2 PKCS#8 documents. If a v2 encoded key is provided to either function, public key component, if present, will be verified to match the one derived from the encoded private key.


Rust developers increasingly need to deploy applications that meet US and Canadian government cryptographic requirements. We evaluated how to deliver FIPS validated cryptography in idiomatic and performant Rust, built around our AWS-LC offering. We found that the popular ring (v0.16) library fulfilled much of the cryptographic needs in the Rust community, but it did not meet the needs of developers with FIPS requirements. Our intention is to contribute a drop-in replacement for ring that provides FIPS support and is compatible with the ring API. Rust developers with prescribed cryptographic requirements can seamlessly integrate aws-lc-rs into their applications and deploy them into AWS Regions.


  • Authenticated Encryption with Associated Data (AEAD).
  • Key Agreement: ECDH, including X25519.
  • Block and Stream Ciphers for Encryption and Decryption.
  • Constant-time operations.
  • SHA-2 and the legacy SHA-1 digest algorithm.
  • Serialization formats
  • Error reporting.
  • HMAC-based Extract-and-Expand Key Derivation Function.
  • HMAC is specified in RFC 2104.
  • ioring-io
    Serialization and deserialization.
  • Initialization Vector (IV) cryptographic primitives
  • Key-Encapsulation Mechanisms (KEMs), including support for Kyber Round 3 Submission.
  • Key Wrap Algorithms.
  • PBKDF2 derivation and verification.
  • PKCS#8 is specified in RFC 5208.
  • Cryptographic pseudo-random number generation.
  • RSA Signature and Encryption Support.
  • Public key signatures: signing and verification.
  • TLS 1.2 PRF API’s for usage in RFC 5246 and RFC 7627.
  • unstableunstable
    Unstable aws-lc-rs features.



  • Initialize the AWS-LC library. (This should generally not be needed.)
  • Indicates whether the underlying implementation is FIPS.