Create A Strong Passcode
You reveal the digits of your code by fingerprint smudges on your smartphone screen.
You can make the passcode you used to unlock your device stronger with a few simple tricks. It turns out that repeating one or two digits in your 6 or 7-digit passcode makes it much stronger. Be sure you use at least six digits.
Here are the details.
A 6-digit passcode is strongest when it contains only 5 distinct digits.
| Distinct digits | Possibilities | |
| 6 | 720 | |
| 5 | 1800 | |
| 4 | 1560 | |
| 3 | 540 | |
| 2 | 62 | |
| 1 | 1 |
For a 7-digit passcode, use only 5 different digits to get the strongest code.
| Distinct digits | Possibilities | |
| 7 | 5040 | |
| 6 | 15120 | |
| 5 | 16800 | |
| 4 | 8400 | |
| 3 | 1806 | |
| 2 | 126 | |
| 1 | 1 |
Note: The 7-digit passcode is over 9 times as strong as the 6-digit code.
The Mathematical Reason Your Passcode Should Repeat A Digit – YouTube video