1. What is Password Entropy?

Password entropy is a measurement of how unpredictable a password is, expressed in bits. The higher the entropy, the more secure the password is against brute-force attacks.

2. How Does the Calculator Work?

The calculator uses the entropy formula:

Where:

• \( possibilities \) — The total number of possible password combinations

Explanation: The formula calculates how many bits of information are needed to represent all possible password combinations.

3. Importance of Password Entropy

Details: Password entropy is crucial for assessing password strength. Higher entropy means the password is more resistant to brute-force attacks.

4. Using the Calculator

Tips: Enter the total number of possible password combinations (based on character set and length). The value must be a positive integer.

5. Frequently Asked Questions (FAQ)

Q1: What is considered good password entropy?
A: Generally, 50-60 bits is good, 60-80 bits is very strong, and 80+ bits is excellent for most purposes.

Q2: How do I calculate possibilities for a password?
A: For a password of length L using C possible characters: possibilities = C^L.

Q3: What's the typical character set size?
A: Lowercase letters: 26, Uppercase: 26, Digits: 10, Special chars: ~32, making 94 for full mixed set.

Q4: Does entropy measure all aspects of password strength?
A: No, it doesn't account for dictionary attacks or common patterns. It measures brute-force resistance.

Q5: How does entropy relate to cracking time?
A: Each additional bit doubles the time needed to crack the password on average.