dcrypt: A Modern, High-Assurance Cryptographic Library in Rust

dcrypt (Decentralized Cryptography) is a comprehensive cryptographic library implemented entirely in safe Rust. It bridges the gap between traditional security and the post-quantum future by providing NIST-standardized Post-Quantum Cryptography (PQC) algorithms alongside novel, production-ready hybrid constructions.

Spearheaded by the IOI Foundation as the security cornerstone for next-generation decentralized infrastructure, dcrypt eliminates foreign function interfaces (FFI) and unsafe code blocks in cryptographic logic, ensuring memory safety and cross-platform compatibility from embedded devices to enterprise servers.

🚀 Novel Capabilities

dcrypt introduces capabilities critical for the transition to quantum-safe computing:

1. Pure-Rust FIPS 204 (ML-DSA): A production-ready implementation of the complete CRYSTALS-Dilithium signature scheme with zero unsafe code and full constant-time execution.
2. Pure-Rust FIPS 203 (ML-KEM): A complete implementation of CRYSTALS-Kyber with protections against timing side-channels.
3. Native Hybrid Cryptography: First-class support for hybrid Key Encapsulation Mechanisms (e.g., ECDH P-256 + Kyber-768) and hybrid Digital Signatures, ensuring security even if one underlying primitive is compromised.

🛡️ Key Design Principles

• Pure Rust & Memory Safety: Implemented with zero FFI dependencies to eliminate memory vulnerabilities like buffer overflows and use-after-free errors common in C/C++ wrapped libraries.
• Post-Quantum Ready: Full support for NIST-selected algorithms, protecting data against "Harvest Now, Decrypt Later" attacks.
• Defense-in-Depth: Hybrid schemes combine battle-tested classical algorithms (ECDH/ECDSA) with modern PQC primitives.
• Constant-Time Execution: All primitives handling secret data are engineered to be branch-free and memory-access-pattern-free. This is enforced by a built-in Constant-Time Verification Suite that statistically detects timing leaks during CI.
• Type Safety: High-level APIs prevent misuse through strong typing (e.g., distinct types for Nonce, Key, and Tag prevents byte-array confusion).
• no_std & Cross-Platform: Fully functional in no_std environments (requiring alloc), making it suitable for IoT, embedded systems, and WASM targets.

📦 Quick Start

Add dcrypt to your project's Cargo.toml.

[dependencies]
dcrypt = { version = "1.0" }

Example 1: Hybrid Post-Quantum Key Exchange

Securely exchange keys using a hybrid scheme (EcdhP256 + Kyber768). This ensures security remains intact even if quantum computers break elliptic curve cryptography.

use dcrypt::hybrid::kem::EcdhP256Kyber768;
use dcrypt::api::Kem;
use rand::rngs::OsRng;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut rng = OsRng;

    // 1. Alice generates a Hybrid Keypair
    // (Contains both a P-256 keypair and a Kyber-768 keypair)
    let (alice_pk, alice_sk) = EcdhP256Kyber768::keypair(&mut rng)?;

    // 2. Bob encapsulates a shared secret against Alice's public key
    let (ciphertext, shared_secret_bob) = EcdhP256Kyber768::encapsulate(&mut rng, &alice_pk)?;

    // 3. Alice decapsulates the ciphertext to recover the shared secret
    let shared_secret_alice = EcdhP256Kyber768::decapsulate(&alice_sk, &ciphertext)?;

    // 4. Verify secrets match
    assert_eq!(shared_secret_bob.as_ref(), shared_secret_alice.as_ref());
    println!("Hybrid Quantum-Safe Key Exchange successful!");
    
    Ok(())
}

Example 2: Authenticated Encryption (AES-256-GCM)

Standard symmetric encryption remains a core part of the library, featuring ergonomic key management.

use dcrypt::symmetric::aes::{Aes256Gcm, Aes256Key};
use dcrypt::symmetric::cipher::{SymmetricCipher, Aead};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Generate a secure random key
    let key = Aes256Key::generate();
    let cipher = Aes256Gcm::new(&key)?;
    
    let nonce = Aes256Gcm::generate_nonce();
    let plaintext = b"Quantum resistance is futile... actually it's necessary.";
    let aad = Some(b"metadata".as_slice());
    
    // Encrypt
    let ciphertext = cipher.encrypt(&nonce, plaintext, aad)?;
    
    // Decrypt
    let decrypted = cipher.decrypt(&nonce, &ciphertext, aad)?;
    
    assert_eq!(plaintext.to_vec(), decrypted);
    Ok(())
}

📚 Supported Algorithms

dcrypt provides a unified API for classical, post-quantum, and hybrid operations:

🏗️ Architecture

The library is organized as a workspace of specialized crates to align type-safety boundaries with security boundaries:

• dcrypt-api: Defines core traits (SymmetricCipher, Kem, Signature), error types, and fundamental data structures.
• dcrypt-algorithms: Low-level, constant-time implementations of cryptographic kernels (hashing, curve arithmetic, lattice math).
• dcrypt-common: Shared security primitives, including SecretBuffer (automatic zeroization) and SecureCompare.
• dcrypt-symmetric: High-level AEADs, stream ciphers, and secure key management wrappers.
• dcrypt-kem: implementations of Key Encapsulation Mechanisms (Kyber, ECDH, McEliece placeholders).
• dcrypt-sign: Implementations of Digital Signatures (Dilithium, ECDSA, Ed25519, SPHINCS+ placeholders).
• dcrypt-hybrid: Ready-to-use combiners for KEMs and Signatures ensuring crypto-agility.
• dcrypt-tests: Contains the ACVP test harness and Constant-Time Verification Suite.

🔒 Security & Verification

Security is the primary driver for dcrypt. The library employs a rigorous testing methodology:

Constant-Time Verification

We utilize a custom statistical analysis engine (dcrypt-tests/src/suites/constant_time) that integrates into our CI.

• Methodology: Uses Welch’s t-test, Kolmogorov–Smirnov tests, and Bootstrap resampling on high-resolution timing measurements.
• Dynamic Threshold Scaling: Adapts to environmental noise (OS jitter) to prevent false positives in CI environments.
• Coverage: Verifies critical paths in Kyber, Dilithium, ECDH, and AES-GCM against timing side-channels.

FIPS/NIST Compliance

• ACVP Test Harness: Includes a full test harness compatible with NIST's Automated Cryptographic Validation Program (ACVP) JSON vectors to ensure implementation correctness against official standards.
• Parameters: All PQC parameters strictly adhere to FIPS 203 (ML-KEM) and FIPS 204 (ML-DSA).

📄 License

This project is licensed under the Apache License, Version 2.0.