新着

パスワード生成器

カスタマイズ可能な長さと文字セットで暗号学的に安全なパスワードを生成します。強度インジケーター付き。

生成されたパスワード
>W]cM(l8o{O4YXiD
強い
16
4128
文字セット
パスワードはWeb Crypto APIを使用してブラウザ内でローカルに生成されます。データがサーバーに送信されることはありません。

How to Use This Tool

  1. 1

    Set the password length

    Use the slider to choose a length between 4 and 128 characters. Longer passwords are exponentially more secure.

  2. 2

    Select character types

    Toggle uppercase letters, lowercase letters, numbers, and symbols on or off. At least one type must remain enabled.

  3. 3

    Generate and review

    A strong password is generated automatically. The color-coded strength meter shows weak, fair, good, or strong ratings based on entropy.

  4. 4

    Copy to clipboard

    Click the 'Copy' button to copy your new password. Click 'Generate' again for a fresh password with the same settings.

Frequently Asked Questions

How are the passwords generated?
Passwords are generated using the Web Crypto API (crypto.getRandomValues), which provides cryptographically secure random numbers. No passwords are sent to or stored on any server.
What makes a password strong?
Password strength depends on length and character variety. A 16-character password with uppercase, lowercase, numbers, and symbols has about 105 bits of entropy — far beyond what brute-force attacks can crack.
How long should my password be?
Security experts recommend at least 12–16 characters for general accounts and 20+ characters for sensitive accounts like banking and email. Our tool supports up to 128 characters.
Is it safe to generate passwords in the browser?
Yes. Everything runs client-side in your browser. No data is transmitted over the network. You can verify this by using the tool offline after the page loads.