Four Words Beat P@ssw0rd
Look at P@ssw0rd. The password has a capital letter, a symbol, a number and eight characters, so most sign-up pages would call it strong.
Yet Have I Been Pwned, a public collection of leaked passwords, has seen P@ssw0rd more than 6 million times. (That count is from October 2026, and the count keeps growing.) A password cracker tries P@ssw0rd in its first second of work.
Collections like that one grew from leaks. In December 2009, an attacker broke into RockYou, a company that made apps for Facebook and MySpace. RockYou had saved about 32 million passwords exactly as people typed them, and the whole list ended up online.
Nearly 1 in every 100 RockYou accounts used 123456. The RockYou list became the first thing crackers try. Your password can sit on a list like that without ever leaking: someone else only had to pick the same password first.
Make your guess. A cracker has a stolen list of scrambled passwords and one gaming graphics card. Which password lasts longest?
P@ssw0rd1!(capitals, symbols and numbers)otter velvet canyon pickle(four plain words)- Both fall in about the same time
Show answer
B. otter velvet canyon pickle (four plain words)
The four plain words last far longer. P@ssw0rd1! falls in under a second, because crackers try the tricks everyone uses. Four words picked at random keep that graphics card busy for hours, and for thousands of years if the website scrambled the password well.
Start with the most famous bad password of all, and try to save it.
Crack a password
Your goal: make password last 100 years. Try all four tricks first, then add random words.
All four tricks together multiplied the guesses by about 6,000, and the cracker still won in under a second. One random word multiplied the guesses by 7,776 on its own, and every extra word multiplied them again. Why do the tricks buy so little?
How crackers guess
A cracker doesn't start at aaaa and count up to zzzz. A cracker guesses in order of what people actually pick.
First come leaked passwords, from most to least common: billions of real choices by real people. Next come dictionary words with the usual tricks: a capital first letter, @ for a, 0 for o, and 1 or ! on the end. Only after those does the cracker try every combination of characters, called brute force.
The tricks fail because everyone uses the same tricks. Crackers have studied millions of leaked passwords, so a capital first letter and a ! on the end are among the first variations a cracker tries.
Which password takes a cracker more guesses?
Sunshine1!qk7wzt- About the same number
Show answer
B. qk7wzt
qk7wzt is shorter and has no capital or symbol, yet the jumble takes about 2 billion guesses: 36 choices (26 letters and 10 digits) for each of 6 random characters. Sunshine1! is a common word plus common tricks, found in under a million guesses. What counts is how random a password is, not how messy the password looks.
So randomness is what counts, and each random piece multiplies the guesses. How fast do the guesses pile up?
Why length wins
Start with random words. A word list built for dice has 7,776 words, because five dice can land 6 × 6 × 6 × 6 × 6 = 7,776 ways. One word rolled from the list takes up to 7,776 guesses.
Two words take 7,776 × 7,776 guesses, about 60 million. Each new word multiplies the guesses by 7,776 again: every random piece multiplies.
Then divide by the speed. One gaming graphics card can test about 100 billion guesses a second against a fast scramble. At that speed four random words fall within about 10 hours, five words last about 9 years, and six words last about 70,000 years.
Show the full working (try it yourself first)
- Count the choices for one piece. A random lowercase letter has 26 choices. A random key on a keyboard has about 95 (letters, capitals, digits and symbols). A word rolled from the dice list has 7,776.
- Multiply for every piece. Eight random keys and four random words come out almost the same, but the four words are far easier to remember:
\[ 95^8 \approx 6.6 \times 10^{15} \qquad 7776^4 \approx 3.7 \times 10^{15} \]3. Divide by the speed. At 100 billion guesses a second, trying every four-word password takes
\[ \frac{3.7 \times 10^{15}}{10^{11}\ \text{per second}} = 3.7 \times 10^{4}\ \text{s} \approx 10\ \text{hours} \]On average the cracker hits the right one halfway through: about 5 hours.
- Count in bits. Security people measure a password in bits: the number of times you would double 1 to reach the number of guesses.
\[ \text{bits} = \log_2(\text{guesses}) \qquad \log_2 7776 \approx 12.9 \]Each random word adds about 12.9 bits, and each random key adds about 6.6 bits. Every extra bit doubles the cracker's work. Four words give about 52 bits, and six words give about 78 bits.
- Price the tricks. A capital first letter doubles the guesses: 1 bit. A symbol on the end multiplies them by about 32: 5 bits. All four tricks in the game add about 12.6 bits, less than one random word, and a password gets to use each trick only once.
But how can a cracker test 100 billion guesses a second? No website answers logins that fast. The answer: the cracker never asks the website.
What websites store
A careful website never saves your password. The site saves a scrambled version called a hash: a fingerprint made by a math recipe that is quick to run forward and practically impossible to run backward.
When you log in, the site scrambles what you typed and compares the new fingerprint with the saved one. A match lets you in, so the site never needs to keep your actual password.
Hackers steal the fingerprints, though, and take the stolen list home. At home nothing slows the cracker down: guess a password, scramble the guess, compare, billions of times a second.
Your goal: crack the three stolen accounts. Tap guesses from the leaked list until a fingerprint matches.
The guess sunshine cracked two accounts at once. mia_k and sam99 both chose sunshine, so both accounts had the same fingerprint. leo.r used four random words, which no leaked list contains.
Good sites stop that double win with salt: a few random characters, different for every account, mixed into the password before scrambling. The same password with a different salt gives a different fingerprint, so the cracker has to attack each account separately.
Good sites also pick a scramble that is slow on purpose, such as bcrypt or Argon2. Against a fast scramble, one graphics card tests about 100 billion guesses a second. Against a slow scramble, the same card may manage 10,000 a second or fewer, depending on the settings.
| Password | Fast scramble | Slow scramble |
|---|---|---|
P@ssw0rd1! | instantly | seconds |
| 8 random keys | 18 hours | 21,000 years |
| 4 random words | 10 hours | 12,000 years |
| 5 random words | 9 years | 90 million years |
| 6 random words | 70,000 years | 700 billion years |
Each time is for one gaming graphics card trying every option. An attacker with many cards goes faster, so leave a margin.
Mike Pound runs real cracking software against a leaked list in this video from Computerphile. Graphics cards have become much faster since 2016.
You can't choose how a website stores your password, and some websites store passwords badly. When one site leaks, what happens to your other accounts?
One leak, many doors
Hackers who steal emails and passwords from one site try every pair on other sites. The attack is called credential stuffing, and bots run it against thousands of sites at once.
Your goal: leak the pizza shop with the same password everywhere. Then switch to one password per site, and then turn on two-factor.
One password per site keeps a leak small. Nobody can remember a hundred random passwords, so a password manager remembers them: an app that makes a long random password for every site and fills the password in for you. You remember one strong passphrase, the one that unlocks the manager.
Two-factor adds a second proof that a stolen password can't supply, such as a code from an app on your phone or a small security key. Turn two-factor on for your email first. Whoever controls your email can reset the password of almost every other account.
So where do these ideas show up in your everyday life?
Where you meet this
- Sign-up rules are changing. The US standards agency NIST now tells websites to stop demanding mixes of symbols and numbers, and to check every new password against leaked lists instead.
- Your browser already checks. Most browsers and phones can suggest random passwords and warn you when a saved password shows up in a leak.
- Passkeys skip the password. Many sites now let you log in with your phone's face or fingerprint unlock. The site keeps only a lock that is useless to a thief, so a leak gives away nothing to reuse.
Four words, answered
Now the opening puzzle makes sense. P@ssw0rd1! uses the same tricks as everyone else, so the password sits near the front of every cracker's list. Four random words force the cracker to count through about 3.7 quadrillion options, and a slow scramble stretches the count to thousands of years.
Give every site its own random password, kept by a password manager, add two-factor to your email, and one leak stays one leak.
Where to go next
This page opens bigger questions. These are the ones worth chasing:
- How can a scramble be easy to run forward and impossible to run backward?
- A hash can't be undone, but my messaging app unscrambles my messages. How is encryption different from hashing?
- A fake login page can steal even a perfect password. How does phishing work, and how do passkeys stop it?
- How does an authenticator app make a fresh six-digit code every 30 seconds, even with no signal?
- Graphics cards get faster every year. How do slow scrambles like bcrypt and Argon2 keep up?
What to learn next: search for “cryptographic hash functions”, then “public-key encryption”, then “phishing and passkeys”. Each topic builds on the fingerprint idea you just used. Computerphile's video "How to Choose a Password" is a good companion.
Ask Phy
- Walk me through how salt and a slow hash like bcrypt protect a stolen password list.
- Is a long password made of song lyrics as strong as six random words? Count the guesses for me.
- Explain step by step how a passkey logs me in without ever sending a password.