Password Strength Checker

Project Overview: Build a working password strength checker in Google Sheets using formulas, and learn the cybersecurity principles behind what makes a password strong or easy to crack. NOTE: Never enter real passwords into any tool! Always use made up example passwords for testing. 

Materials: 

• A computer 

• A free Google account

Instructions: 

1. Create a new blank spreadsheet, named “Password Strength Checker”,  on sheets.google.com. In cell A1 type “Enter Password:” and leave cell B1 empty. The cell will instead be used to type passwords to test. 

2. In cells A2 through A6, type the following labels, one per row:

   1. At least 8 characters?

   2. Contains uppercase letter?

   3. Contains lowercase letter?

   4. Contains a number?

   5. Contains a special character?

3. In cell B2, type the following formula to check if the password is at least 8 characters long: =IF(LEN(B1)>=8,"✅","❌")

   1. LEN counts the number of characters in the password. If it is 8 or more, it shows a checkmark. Otherwise it shows a cross. 

4. In cell B3, type: =IF(REGEXMATCH(B1,”[A-Z]”),"✅","❌")

   1. REGEXMATCH searches the password for any character matching the pattern. In this case, any uppercase letter from A to Z.

5. In cell B4, type: =IF(REGEXMATCH(B1,”[a-z]”),"✅","❌")

6. In cell B5, type: =IF(REGEXMATCH(B1,”[0-9]”),"✅","❌")

7. In cell B6, type: =IF(REGEXMATCH(B1,"[^a-zA-Z0-9]"),"✅","❌")

   1. The [^a-zA-Z0-9] pattern means "anything that is NOT a letter or number".

8. In cell A7 type "Strength Score:" and in B7 type: =COUNTIF(B2:B6,"✅")

   1. This counts how many criteria the password passed out of 5. A score of 5 means the password passed every check!

9. In cell A8 type "Strength Rating:" and in B8 type: =IF(B7<=2,"⚠️ Weak",IF(B7<=4,"🟡 Fair","✅ Strong"))

   1. This uses nested IF statements to label the password as Weak, Fair, or Strong based on the score.

10. Select cell B8, then go to Format → Conditional formatting. Set it to highlight red when the cell contains "Weak", yellow for "Fair", and green for "Strong." Now your checker gives visual feedback just like a real tool!

11. Type some sample passwords into cell B1 and watch the checker evaluate them in real time. Which ones pass? Which ones fail? Do the results surprise you?