id: crypto title: Crypto custom_edit_url: https://github.com/libra/libra/edit/master/crypto/crypto/README.md

Crypto

The crypto component hosts all the implementations of cryptographic primitives we use in Libra: hashing, signing, and key derivation/generation. The parts of the library usig traits.rs contain the crypto API enforcing type safety, verifiable random functions, EdDSA & BLS signatures.

Overview

Libra makes use of several cryptographic algorithms:

• SHA-3 as the main hash function. It is standardized in FIPS 202. It is based on the tiny_keccak library.
• HKDF: HMAC-based Extract-and-Expand Key Derivation Function (HKDF) based on RFC 5869. It is used to generate keys from a salt (optional), seed, and application-info (optional).
• traits.rs introduces new abstractions for the crypto API.
• Ed25519 performs signatures using the new API design based on ed25519-dalek library with additional security checks (e.g. for malleability).
• BLS12381 performs signatures using the new API design based on threshold_crypto library. BLS signatures currently undergo a standardization process.
• ECVRF implements a verifiable random function (VRF) according to draft-irtf-cfrg-vrf-04 over curve25519.
• SLIP-0010 implements universal hierarchical key derivation for Ed25519 according to SLIP-0010.
• X25519 to perform key exchanges. It is used to secure communications between validators via the Noise Protocol Framework. It is based on the x25519-dalek library.

How is this module organized?

    crypto/src
    ├── hash.rs             # Hash function (SHA-3)
    ├── hkdf.rs             # HKDF implementation (HMAC-based Extract-and-Expand Key Derivation Function based on RFC 5869)
    ├── macros/             # Derivations for SilentDebug and SilentDisplay
    ├── utils.rs            # Serialization utility functions
    ├── lib.rs
    ├── bls12381.rs         # Bls12-381 implementation of the signing/verification API in traits.rs
    ├── ed25519.rs          # Ed25519 implementation of the signing/verification API in traits.rs
    ├── slip0010.rs         # SLIP-0010 universal hierarchical key derivation for Ed25519
    ├── x25519.rs           # X25519 keys generation
    ├── test_utils.rs
    ├── traits.rs           # New API design and the necessary abstractions
    ├── unit_tests/         # Tests
    └── vrf/
        ├── ecvrf.rs        # ECVRF implementation using curve25519 and SHA512
        ├── mod.rs
        └── unit_tests      # Tests