Cryptography Best Practices for Developers

What this best practices guide is

A practical cryptography guide for application developers, not cryptographers. It covers choosing the right primitive and a high-level library, authenticated encryption and nonces, secure randomness, key management with KMS and rotation, TLS configuration, and how to prepare for post-quantum algorithms with crypto agility.

It has 6 chapters and 24 practices, each with why it matters, what to do and what to avoid. For developers who encrypt, sign or hash data.

Chapter by chapter

1. Choosing the right tool and library (4 practices)

Before writing any crypto code, decide which property you need (secrecy, integrity, authenticity) and use a high-level library that gives you exactly that.

2. Encrypting data with AEAD (4 practices)

Authenticated encryption keeps data secret and detects tampering in one step. Most of the risk sits in nonces, associated data and how you encrypt with public keys.

3. Randomness, tokens and key derivation (3 practices)

Keys, nonces, tokens and IDs are only as strong as the random numbers behind them. This chapter covers where to get randomness and how to derive keys from other keys.

4. Key management and rotation (4 practices)

Encryption moves the problem from protecting data to protecting keys. This chapter covers where keys live, envelope encryption, cryptoperiods and rotating without downtime.

5. TLS configuration for servers and clients (5 practices)

TLS protects data in transit, but only with sound protocol settings, well-managed certificates, and clients that actually verify what they connect to.

6. Post-quantum readiness and crypto agility (4 practices)

NIST has standardized the first post-quantum algorithms. This chapter covers what changed, what did not, and how to make your code ready to swap algorithms.

How it works on Sefism

The guide reads like a short course: a syllabus, then one chapter per page in a focused reader, with a quiz at the end of each chapter for members. The opening chapters are open to everyone. Adding it to your account uses credits, opens every chapter and keeps your progress.

Every claim is checked against the sources listed on the page (8 cited).