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dryoc: Don't Roll Your Own Crypto™¹

dryoc is a pure-Rust, general-purpose cryptography library that's hard to misuse. It's based on the excellent libsodium library, but in pure Rust. It also includes protected memory features throughout, which makes it dead simple to build secure, robust, and safe cryptographic software. The original goal of this library was to provide a pure-Rust alternative to libsodium.

The purpose of this project is to provide a pure-Rust, mostly drop-in replacement for libsodium. This library has nearly the same ergonomics as libsodium (referred to in dryoc as the Classic API), such that people familiar with libsodium can use this library nearly interchangeably. While the API is not 100% identical to libsodium, most functions have the same or very similar signatures.

In addition to the Classic API, there's a Rustaceous API which aims to bring an idiomatic Rust implementation of libsodium's core features: public and secret key authenticated cryptography and general-purpose cryptography tools.

Not all features from libsodium are implemented here, either because there exist better implementations in other crates, or because they aren't necessary as part of this crate.

Additionally, this crate provides exceptionally safe cryptography thanks to Rust's safety features. The Rustaceous API is designed designed to make it difficult to shoot yourself in the foot. It's worth noting, however, you certainly can still shoot yourself if you choose (either by leaking private data, using insecure hardware, OPSEC issues, etc).

For example usage, refer to the official docs or the integration tests.

Features

• 100% pure Rust, no hidden C libraries
• mostly free of unsafe code²
• Hard to misuse, helping you avoid common costly cryptography mistakes
• Many libsodium features implemented with both Classic and Rustaceous API
• Protected memory handling (mprotect() + mlock(), along with Windows equivalents)
• Serde support (with features = ["serde"])
• Portable SIMD implementation for Blake2b (used by generic hashing, password hashing, and key derivation) on nightly, with features = ["simd_backend", "nightly"]
• SIMD backend for Curve25519 (used by public/private key functions) on nightly with features = ["simd_backend", "nightly"]
• SHA2 (used by sealed boxes) includes SIMD implementation for AVX2
• ChaCha20 (used by streaming interface) includes SIMD implementations for Neon, AVX2, and SSE2

To enable all the SIMD backends through 3rd party crates, you'll need to also set RUSTFLAGS:

• For AVX2 set RUSTFLAGS=-Ctarget-cpu=haswell -Ctarget-feature=+avx2
• For SSE2 set RUSTFLAGS=-Ctarget-feature=+sse2
• For Neon set RUSTFLAGS=-Ctarget-feature=+neon

Note that eventually this project will converge on portable SIMD implementations for all the core algos which will work across all platforms supported by LLVM, rather than relying on hand-coded assembly or intrinsics, but his is a work in progress.

Project status

The following libsodium features are currently implemented, or awaiting implementation:

• Public-key cryptography (crypto_box_*) libsodium link
• Secret-key cryptography (crypto_secretbox_*) libsodium link
• Point*scalar multiplication (crypto_scalarmult*) libsodium link
• Zeroing memory (sodium_memzero) with zeroize libsodium link
• Generating random data (randombytes_buf) libsodium link
• Encrypted streams (crypto_secretstream_*) libsodium link
• Memory locking (sodium_mlock, sodium_munlock, sodium_mprotect_*) libsodium link
• Encrypting related messages (sodium_increment) libsodium link
• Generic hashing (crypto_generichash_*) libsodium link
• Secret-key authentication (crypto_auth*) libsodium link
• One-time authentication (crypto_onetimeauth_*) libsodium link
• Sealed boxes (crypto_box_seal*) libsodium link
• Key derivation (crypto_kdf_*) libsodium link
• Key exchange (crypto_kx_*) libsodium link
• Public-key signatures (crypto_sign_*) libsodium link
• Ed25519 to Curve25519 (crypto_sign_ed25519_*) libsodium link
• Short-input hashing (crypto_shorthash) libsodium link
• Password hashing (crypto_pwhash_*) libsodium link

The following libsodium features are either incomplete, not exposed as public APIs, or not implemented; you may find equivalent functionality in other crates:

• Stream ciphers (use salsa20 crate directly instead)
• Helpers and padding utilities
• Advanced features:
  • Scrypt (use scrypt crate directly instead)
  • Finite field arithmetic (try the curve25519-dalek crate)

Stargazers over time

Other NaCl-related Rust implementations worth mentioning

• sodiumoxide
• crypto_box

Footnotes

1. Not actually trademarked. ↩

2. The protected memory features described in the [protected] mod require custom memory allocation, system calls, and pointer arithmetic, which are unsafe in Rust. Some of the 3rd party libraries used by this crate, such as those with SIMD, may contain unsafe code. In particular, most SIMD implementations are considered "unsafe" due to their use of assembly or intrinsics, however without SIMD-based cryptography you may be exposed to timing attacks. ↩