1. What is Password Entropy?

Password entropy measures the unpredictability of a password in bits. Higher entropy means the password is more secure against brute-force attacks.

2. How Does the Calculator Work?

The calculator uses the entropy formula:

Where:

• \( charset\_size \) — Number of possible characters in the character set
• \( length \) — Length of the password in characters

Explanation: The formula calculates how many bits of information are contained in the password based on its length and the size of the character set used.

3. Importance of Password Entropy

Details: Password entropy is crucial for security. Passwords with low entropy can be cracked quickly, while high-entropy passwords provide better protection against brute-force attacks.

4. Using the Calculator

Tips: Enter the size of your character set (e.g., 26 for lowercase letters, 62 for alphanumeric) and your password length. Both values must be positive integers.

5. Frequently Asked Questions (FAQ)

Q1: What's considered good password entropy?
A: Generally, aim for at least 64 bits of entropy for important accounts. 128+ bits is considered very secure.

Q2: How do I determine my character set size?
A: Count all possible characters in your password. Example: lowercase (26), uppercase (26), digits (10), symbols (32) = 94 total.

Q3: Does this account for common password patterns?
A: No, this calculates theoretical maximum entropy. Real-world passwords often have lower effective entropy due to patterns.

Q4: How does length affect entropy?
A: Increasing length exponentially increases entropy, making it the most important factor for strong passwords.

Q5: What's the relationship between entropy and cracking time?
A: Each additional bit of entropy doubles the time needed for a brute-force attack (on average).