iwantcoding.com
🔥 Daily 👥 Rooms 🏆 Top Log in Sign up

Safe Libraries

By · Reviewed & last updated · Part of Cryptography Tutorial

Pick the cryptography library once per language and stay with it. The right libraries have constant-time primitives, are audited, and present misuse-resistant APIs. Roll-your-own crypto, deprecated wrappers, and obscure ports are how applications grow a vulnerability they cannot patch without a migration.

The right crypto library per ecosystem

EXAMPLE
# ===== Python =====
# pip install cryptography
# Use:
#   AES-GCM:     cryptography.hazmat.primitives.ciphers.aead.AESGCM
#   X25519:      cryptography.hazmat.primitives.asymmetric.x25519
#   Ed25519:     cryptography.hazmat.primitives.asymmetric.ed25519
#   HKDF:        cryptography.hazmat.primitives.kdf.hkdf.HKDF
#   Argon2id:    argon2-cffi (separate package)
#   Constant time compare: hmac.compare_digest
# Avoid: pycrypto (unmaintained), Crypto.* in old codebases, hand-rolled ChaCha.

# ===== Node.js =====
# Built-in: node:crypto (covers most needs)
#   AES-GCM:        createCipheriv('aes-256-gcm', ...)
#   X25519/Ed25519: generateKeyPair / sign / verify
#   HKDF:           crypto.hkdfSync('sha256', ...)
#   Argon2id:       argon2 (npm package)
#   timingSafeEqual for compares
# When you need libsodium semantics: npm i libsodium-wrappers-sumo
# Avoid: crypto-js (browser-only string toys), js-sha256 hand-rolls.

# ===== Go =====
# Standard library covers most:
#   crypto/aes + crypto/cipher.NewGCM
#   crypto/ed25519, golang.org/x/crypto/curve25519
#   crypto/hkdf (Go 1.22+)
#   golang.org/x/crypto/argon2
#   crypto/subtle.ConstantTimeCompare
# When you want a higher-level API: github.com/google/tink-go.
# Avoid: rolling your own AES mode; importing 'unsafe' crypto packages from obscure repos.

# ===== Rust =====
# Use one of:
#   ring                       — fast, audited, opinionated; default for new code
#   rustls (TLS)              — pairs with ring; ships in Hyper, Reqwest
#   aes-gcm, chacha20poly1305 — RustCrypto org crates (also good)
#   ed25519-dalek             — Ed25519 signing
#   x25519-dalek              — X25519 ECDH
#   argon2                    — RustCrypto argon2
# Avoid: openssl bindings for greenfield code (linking pain, larger attack surface).

# ===== PHP =====
# Built-in:
#   sodium_*  (libsodium wrappers, since PHP 7.2) — preferred
#   password_hash / password_verify (argon2id by default in modern PHP)
#   hash_equals for constant-time comparisons
#   openssl_* — fine when sodium does not cover the use case
# Avoid: hand-rolling AES-CBC; phpseclib for new code unless required for legacy SSH.

# ===== Java =====
# Bouncy Castle (org.bouncycastle) for everything not in JDK.
# JDK itself ships AES/RSA/EC; default Cipher.getInstance('AES/GCM/NoPadding').
# Argon2: bcprov-jdk18on or de.mkammerer:argon2-jvm.
# Avoid: SecureRandom defaults that differ across JVMs — explicit instance per vendor.

# ===== .NET =====
# System.Security.Cryptography for AES-GCM, ECDH, ECDsa.
# Konscious.Security.Cryptography for Argon2id.
# Avoid: legacy RijndaelManaged (use Aes/Aes.Create()); DES; MD5 for anything but checksums.

# ===== Universal advice =====
# 1) Prefer the highest-level primitive available (AEAD over raw cipher,
#    password hasher over hash function, HKDF over manual derivation).
# 2) NEVER ship cryptography you wrote yourself if you can avoid it.
# 3) Crypto libraries get audited; auditor reports are public — read them
#    before betting your product on a crate / package.
# 4) Pin the version. Patch quickly. CVE disclosures in crypto libraries
#    are usually critical and quick to exploit.

Why it matters

When choosing a crypto library, the published audit is the trust signal. ring, rustls, libsodium, BoringSSL, BouncyCastle — all have one. A library without a public audit report is not necessarily broken, but it is asking you to trust without verification, and crypto is the worst place to make that trade.

Tip: Tweak the snippet with Try it Yourself », then sit the quiz at the bottom of the page.

Example

Example
// Pick one, learn it well.
// JS/TS:  WebCrypto, libsodium-wrappers, node:crypto, jose, @simplewebauthn
// Python: cryptography, pyca/nacl, jwt (PyJWT)
// Go:     crypto/* stdlib, x/crypto, jose-go
// Rust:   ring, RustCrypto, libsodium-rs
Try it Yourself »

Discussion

Loading…