1. What is Password Entropy?

Definition: Password entropy measures the unpredictability of a password in bits, indicating its strength against brute-force attacks.

Purpose: Helps users and security professionals evaluate password strength and make informed security decisions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( H \) — Entropy in bits
• \( N \) — Size of character set (possible characters)
• \( L \) — Length of password (characters)

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

3. Importance of Password Entropy

Details: Higher entropy means greater password strength. Modern security standards recommend at least 80 bits of entropy for important accounts.

4. Using the Calculator

Tips: Enter the character set size (default 62 for alphanumeric) and password length (default 12). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a good entropy value?
A: 50-70 bits is moderate, 70-100 is strong, and 100+ is very strong security.

Q2: What character set sizes are common?
A: 26 (lowercase), 52 (mixed case), 62 (alphanumeric), ~94 (all printable ASCII).

Q3: How does length affect entropy?
A: Entropy grows linearly with length but exponentially with character set size.

Q4: Does this account for dictionary attacks?
A: No, this measures brute-force resistance only. Avoid dictionary words.

Q5: How can I increase entropy?
A: Use longer passwords and larger character sets (include symbols).