KatakataLab

Created by Katakata · Reviewed

Password security: make the safe choice easier to repeat

Password security is less about inventing a clever string and more about preventing reuse, storing credentials safely, and adding another factor when an account supports it. This guide is educational, not an account-recovery or security-monitoring service.

Short version: use a different password for every important service, prefer a long randomly generated value, store it in a password manager, and enable multi-factor authentication or a passkey where available. Never paste an existing password into a tool just to test it.

Length and uniqueness come first

A password that is reused across services creates a chain reaction: one service breach or phishing page can expose access to another account. A long password or passphrase is useful, but it does not compensate for reuse. Generate a separate value for email, finance, work, social accounts, and other services that matter.

Current NIST SP 800-63B guidance says verifiers should require at least 15 characters when a password is used as a single-factor authentication mechanism, permit at least 64 characters, and avoid arbitrary composition rules as the main security control. These are requirements for services and verifiers, not a promise that every website follows them.

Use a manager instead of memorizing everything

  1. Choose a password manager with a master credential or passkey that you can protect.
  2. Generate a unique random password for each service and let the manager fill it when possible.
  3. Keep recovery codes in a separate, protected place and decide how a trusted person could help if you lose access.
  4. Review old reused passwords first, beginning with email, financial accounts, cloud storage, and administrator accounts.

Password managers make unique passwords practical. They also mean the master credential and recovery process deserve extra care: protect them, keep software updated, and do not approve unexpected sign-in prompts.

Passwords are not phishing-resistant

A strong password can still be entered into a convincing fake login page. Multi-factor authentication reduces the damage of a stolen password, while passkeys are designed to resist many phishing flows. Enable the strongest practical option offered by the service, and verify the domain before entering credentials.

What KatakataLab can and cannot do

The Japanese password generator linked below can create values in the browser and provides local handling notes. A browser-side tool does not make every surrounding action safe: clipboard history, screenshots, browser extensions, device malware, and account recovery settings still matter. Do not use a public page to inspect an existing secret.

Open the password generator (Japanese)

Sources and scope

This guide was reviewed on July 22, 2026. For the normative details behind the length and composition discussion, read NIST SP 800-63B, Authenticators. Provider policies and phishing threats change, so check the current security guidance for the service you use.