Password storage

Password storage: hashing parameters and rehash on login

Choose Argon2id, scrypt, PBKDF2 or bcrypt with current minimum parameters, store a versioned hash, and upgrade old hashes after a successful login without overwriting a reset.

Development · Developers

Choose cryptographic algorithms and parameters by job

A sourced quick reference for October 2026: which algorithm and parameters to use for encryption, hashing, passwords, MACs, signatures, key agreement, key derivation, randomness and TLS, the matching APIs in Node.js, Python, Java, Go and .NET, and where post-quantum migration stands.

Design, Development · Developers

Case study: the LastPass breach (2022)

How an attacker went from a compromised developer laptop to a DevOps engineer's home computer, the keys to LastPass's cloud backups and a copy of customer vaults; why each vault's safety then rested on its master password and PBKDF2 iteration count; and what it teaches about backup keys, privileged endpoints, KDF upgrades and unencrypted metadata.

Design, Development, Maintenance · AppSec engineers, Platform engineers and SREs

Insecure randomness lab: Generate unguessable API keys

An integration service issues 16-character API keys from Math.random, which is not built to be unpredictable. Take every character from the system’s secure generator, lengthen the key and map bytes without bias.

Password hashing lab: Verify and upgrade an Argon2 password hash on login

A login check verifies stored password hashes but never upgrades a weak or outdated one, so hashes created with tiny parameters or the wrong Argon2 variant stay that way forever. Repair check_login to verify with Argon2id at the policy minimum and rehash on a successful login.

Weak password hashing

Weak password hashing turns a leaked users table into a list of passwords.