Understand password best practices, hashing (MD5/SHA/Bcrypt), and how to test strength with online tools—plus what not to log or store.

Passwords, Hashes, and Strength Tests: A Plain-English Guide

Audience: Users, support, and developers
Goal: Create strong passwords, understand hashing basics, and avoid common storage pitfalls.

What makes a good password?

• Length over complexity: 14–20 chars beats short complex strings.
• Mix cases, numbers, symbols; avoid dictionary words and patterns.
• Use unique passwords per site—breach reuse is the #1 risk.
• Prefer a reputable password manager for generation and storage.

Hashing 101

• What a hash is: One-way function; MD5/SHA1/SHA256/etc. turn input into fixed-length output.
• What a hash isn’t: Not encryption; cannot be “decrypted.”
• Why old hashes are weak: MD5/SHA1 are fast and crackable with modern GPUs.
• Use slow, salted password hashing: Bcrypt, scrypt, Argon2. Salt prevents precomputed/rainbow attacks; slowness thwarts brute force.

When to use which hash

• Bcrypt/Argon2/scrypt: Password storage (only on the server, never in the browser for real auth flows).
• SHA-2/SHA-3: Integrity checks (files, messages), not passwords.
• MD5: Legacy checksums only; never for security decisions.

Password strength testing

• Use a strength tester to gauge length/entropy and common pattern risk.
• Never paste real production passwords into unknown tools; for sensitive creds, test locally or with trusted tooling.
• Look for warnings on reuse, dictionary words, leetspeak substitutions, and short length.

Practical tips for teams

• Enforce minimum length (e.g., 14) and block common/breached passwords.
• Enable MFA; it multiplies security for the same password quality.
• Rate-limit login attempts; add breach monitoring for credential stuffing.
• Never store passwords in logs; avoid writing hashes of user-entered passwords client-side.

What to communicate to users

• Use a password manager; don’t reuse passwords.
• Favor passphrases: longer, memorable, fewer reuse temptations.
• MFA is not optional—promote app-based or hardware keys.

Where your tools fit

• Password Generator: Create long, random, unique passwords.
• Password Strength Test: Check for length/entropy/pattern weaknesses.
• Hash Generators (MD5/SHA/Bcrypt): Demonstrate hashing; for real auth, use server-side salted Bcrypt/Argon2.

Bottom line

Length, uniqueness, and MFA matter most. Hash passwords with slow, salted algorithms server-side. Use strength tests for education, not to handle real secrets in untrusted contexts.