Question 1

Is the password generated here secure, and does it stay only in my browser?

Accepted Answer

Yes. Every character is drawn with crypto.getRandomValues, the browser's cryptographic generator, not Math.random. The draw uses bias rejection: values that would make some characters more likely are discarded and drawn again. The password is built on your device, is not sent to any server, is not written to local storage and does not appear in analytics events.

Question 2

Does length matter more than complexity?

Accepted Answer

Almost always. Each extra character multiplies the number of combinations by the alphabet size, while adding one more character type only enlarges that alphabet a little. A random 16-character password drawn from 88 symbols has about 103 bits; with lowercase letters only, 16 characters give about 75 bits, and 20 lowercase letters give about 94. For secrets you have to type, increasing length is the cheapest way to gain entropy.

Question 3

Passphrase or random password: which should I use?

Accepted Answer

A random password is the best choice for anything a password manager fills in for you, because nobody has to type or remember it. A passphrase is the best choice for what you type or memorize yourself: the password manager's master password, the encrypted disk, the Wi-Fi. With the 1024-word list each word is worth 10 bits: 6 words give 60 bits and 8 give 80 bits. The critical point is that the words are drawn by the generator, not chosen by you, because words picked by people follow predictable patterns.

Question 4

What is entropy and how is it computed here?

Accepted Answer

Entropy measures, in bits, the size of the space of possibilities the secret was drawn from. Each bit doubles the number of combinations. For a random password it is length × log2(alphabet size). For a passphrase it is words × log2(1024) = words × 10, plus about 6.6 bits if the 2-digit number is on. For a PIN it is log2(10 to the power of the number of digits): 6 digits give about 19.9 bits. The calculation holds because the draw is uniform, and only applies to drawn secrets: it does not measure a password a human made up.

Question 5

What changes when I require at least one character of each type?

Accepted Answer

Some sites only accept passwords with an uppercase letter, a lowercase letter, a number and a symbol. To comply, the generator draws the whole password and discards the ones that lack any type, repeating until it succeeds. This keeps the distribution uniform among valid passwords, and the entropy shown is the exact one: the logarithm of the number of passwords that meet the rule, computed by inclusion and exclusion. The loss is small (a few bits at 4 characters, almost zero at 16 or more). That is why the calculation appears on screen, with no hidden approximation.

Question 6

Why is crack time only an estimate?

Accepted Answer

Because it depends on who is attacking and how the password was stored, things no web page can see. The screen assumes the attacker knows the generation method, tries in random order and finds the password, on average, after half the combinations: time = 2^(bits - 1) ÷ guesses per second. As a worked example, 60 bits at 10 billion guesses per second give 2^59 ÷ 10^10, about 5.8 × 10^7 seconds, close to 1.8 years. Changing the rate 10 times changes the time 10 times, which is why the three scenarios appear side by side and are labeled as order of magnitude.

Question 7

What is the difference between an online and an offline attack?

Accepted Answer

In an online attack the attacker has to try the password on the service itself, which can limit attempts, lock the account and require a second factor: the rate is low, something like tens or hundreds of guesses per hour per account. In an offline attack the attacker already has the password hashes (for example from a database breach) and tests on their own hardware with no limit at all. There the rate depends on the algorithm: a fast hash with no cost factor allows billions of guesses per second per GPU, while bcrypt, scrypt or argon2 are designed to be slow. Short passwords only survive the online scenario.

Question 8

Why shouldn't I reuse the same password on several sites?

Accepted Answer

Because your weakest sign-up sets the security of all the others. When a service leaks, attackers automatically try that email and password on hundreds of other sites, a technique called credential stuffing. With unique passwords a breach hits one account only. Generate one random password per service and keep it in a manager. To check whether a password you already used has appeared in known breaches, use the leaked password checker, which queries by k-anonymity without sending the whole password.

Question 9

Do I need a password manager?

Accepted Answer

For most people, yes. Unique, long passwords for dozens of accounts do not fit in memory, and a manager stores them encrypted, fills them only on the correct site (helping against phishing) and generates new ones. You memorize one strong passphrase as the master password and leave everything else random. Use a manager that has two-factor authentication and a recovery backup, and never keep passwords in messages, emails or open spreadsheets.

Question 10

Does two-factor authentication (2FA) replace a strong password?

Accepted Answer

No, it adds to it. The second factor protects against someone who found out the password, but the password is still the first barrier, and not all 2FA protects equally: SMS codes can be diverted, authenticator apps help more, and passkeys or hardware keys resist phishing. The ideal setup is a long, unique password plus the strongest 2FA the service offers.

Question 11

Should I change my passwords from time to time?

Accepted Answer

Not on a schedule. NIST SP 800-63B-4, the US government digital identity guideline, says verifiers should not require periodic password changes, and should force a change when there is evidence the password was compromised. The same document says composition rules (like requiring a symbol) should not be imposed and requires checking against a blocklist of common or compromised passwords. Forced rotation produces predictable passwords (Password1, Password2). Change when there is a sign of a leak, suspected unauthorized access or when the password was shared.

Question 12

Why do some sites reject the password I generated?

Accepted Answer

Many sites cap the maximum length, refuse certain symbols or require specific character types. Open Adjust password: edit the allowed symbols list (the Most accepted only button gives a safe list), type in Exclude these characters the ones the site refuses, reduce the length or use Require at least one of each type. If the site caps the password at a few characters or bans symbols, compensate by using the full allowed length, and consider turning on 2FA, since the password alone ended up limited.

Scenario	Average time
Online, rate limited	`about 10^24 years`
Offline, slow hash	`about 10^19 years`
Offline, fast hash	`about 10^13 years`

Scenario	Average time
Online, rate limited	`about 10^24 years`
Offline, slow hash	`about 10^19 years`
Offline, fast hash	`about 10^13 years`

Password Generator