Password Security Guide: Create Strong, Uncrackable Passwords
6 min read · Updated 2025
Every year, billions of account credentials are exposed in data breaches. The most common passwords are still "123456," "password," and "qwerty" — easily cracked in milliseconds. This guide explains how hackers crack passwords, what makes one truly strong, and how to build a secure password system you can actually maintain.
How Hackers Crack Passwords
- Brute force: Trying every possible combination. A 6-character lowercase password has only 309 million combinations — cracked in seconds by modern hardware.
- Dictionary attacks: Trying every word in a dictionary, plus common substitutions (p@$$w0rd, passw0rd). Defeats most "clever" passwords.
- Credential stuffing: Using leaked username/password pairs from one breach to attack other sites. If you reuse passwords, one breach exposes all accounts.
- Phishing: Tricking you into entering your password on a fake website. No amount of password complexity defeats this — multi-factor authentication (MFA) does.
What Makes a Password Strong?
Length: 12+ characters
Length is the biggest factor. Each extra character multiplies the search space exponentially.
Mix of character types
Uppercase, lowercase, numbers, and symbols dramatically increase complexity.
No dictionary words
Even substituting letters (3 for E) is no longer effective — attackers account for this.
Unique per site
Never reuse passwords. One breach should not expose all your accounts.
Password Strength by Length
| Length | Character Set | Combinations | Time to crack (GPU) |
|---|---|---|---|
| 6 | Lowercase only | 309 million | Instantly |
| 8 | Upper + lower + numbers | 218 trillion | Hours |
| 12 | Upper + lower + numbers + symbols | 475 quadrillion | Centuries |
| 16 | Upper + lower + numbers + symbols | 4.6 × 10²⁸ | Heat death of universe |
The Passphrase Method
An alternative to random passwords: use 4–5 random unrelated words joined together. Example: correct-horse-battery-staple. This is 28 characters long, easy to type, and near-impossible to brute force — while being far easier to remember than X#9kqZ$2mP&v.
Multi-Factor Authentication (MFA)
Even a strong password can be stolen via phishing. Enable MFA on every important account. Even SMS-based MFA (the weakest form) blocks over 99% of automated attacks. Authenticator apps (Google Authenticator, Authy) and hardware keys (YubiKey) are even stronger.
Generate a strong random password instantly with BrainBoost's free Text Encryption tool. Also see the Base64 Encoder and Base64 Encoding guide.