🛡️ Sealed in Rust — A Practical Guide to Cryptography

Build secure systems with the language of safety.

Learn cryptography hands-on, one primitive at a time.

From XOR to Ed25519 — understand, implement, and apply.

Why This Book

• Most cryptography resources focus on abstract theory rather than practical applications in Rust.
• This book is designed to help Rust developers build secure systems without requiring a background in academic cryptography.

Prefer to learn by watching? 🎥 Follow the Fearless in Rust: Cryptography playlist.

Roadmap

The book is organized into four parts, each designed to bridge practical cryptography with real-world Rust engineering.

Part 1 — Foundations of Applied Cryptography

• Why cryptography is a systems problem
• Rust’s guarantees: memory safety, performance, and predictability
• Case studies on security failures
• Tooling, mindset, and first secure implementations (XOR)

Part 2 — Core Cryptographic Primitives

• Symmetric ciphers: XOR, AES, ChaCha20
• Message authentication codes: HMAC, Poly1305
• Public-key cryptography: Ed25519, ECDSA, RSA
• Hash functions, KDFs, AEAD, randomness
• Road to ZKPs and post-quantum crypto

Part 3 — Real-World Domains

This part demonstrates how cryptographic primitives are applied across high-impact sectors, each with unique threat models and system constraints. Topics include architecture, Rust design patterns, and domain-specific security challenges.

Domains include:

• Secure Infrastructure
• Blockchain & Web3
• Healthcare & Medical Systems
• Defense & Aerospace
• Identity & Access Systems
• Embedded & IoT Systems
• Privacy-Preserving AI
• Offensive Security & Red Teaming

Part 4 — Building a Secure Rust Crate

• Safe-by-design API architecture
• Modular code for reusability and auditability
• Testing (unit, property-based, fuzzing)
• Documentation, publishing, and maintenance best practices

Follow Updates

• Progress is documented weekly on Linkedin, Mastodon and Bluesky
• Feedback, suggestions, and pull requests are welcomed via GitHub

Diagrams and Supplementary Content

Book Part 2 - Core Cryptographic Primitives

Book Part 3 - Real-World Domains