Generate cryptographically secure random passwords.
Humans are notoriously bad at creating random passwords. We tend to use patterns, dictionary words, and personal information that attackers can easily guess. A cryptographically secure random password generator creates passwords that are truly unpredictable and resistant to all forms of password attacks.
This generator uses your browser's cryptographic random number generator (crypto.getRandomValues() or Python's secrets module) to ensure each character is selected with genuine randomness—not pseudo-randomness that could be predicted.
Length is the most important factor in password security. Each additional character exponentially increases the number of possible combinations.
Using multiple character types increases the "key space" attackers must search.
Entropy measures the randomness of a password in bits. Higher entropy means more possible combinations and greater security. The formula is:
Entropy = log₂(character_pool_size^password_length)
| Password Configuration | Pool Size | 8 chars | 12 chars | 16 chars |
|---|---|---|---|---|
| Lowercase only | 26 | 37.6 bits | 56.4 bits | 75.2 bits |
| Mixed case | 52 | 45.6 bits | 68.4 bits | 91.2 bits |
| Mixed + numbers | 62 | 47.6 bits | 71.5 bits | 95.3 bits |
| All character types | 94 | 52.4 bits | 78.7 bits | 104.9 bits |
Modern password cracking can attempt billions of guesses per second. Here's how long different passwords would take to crack:
| Password Type | Time to Crack (10B guesses/sec) |
|---|---|
| 6 lowercase letters | Less than 1 second |
| 8 lowercase letters | About 20 seconds |
| 8 mixed case + numbers | About 19 hours |
| 12 all character types | About 3,000 years |
| 16 all character types | Longer than universe age |
While random passwords are secure, they're hard to memorize. An alternative is a passphrase—a sequence of random words:
Example passphrase:
correct-horse-battery-staple
This 28-character passphrase is easier to remember than a random 12-character password but has comparable entropy (~44 bits for 4 common words, more with modifications).
The best way to use strong, unique passwords is with a password manager:
While special characters increase entropy, some systems have restrictions:
If you encounter issues, try generating without special characters and compensate with extra length.