This is a link post for some of the regular expressions that can be used for passwords. Specifically, you can use them for asp.net's passwordStrengthRegularExpression. Note: Be sure to test them *before* you use them in a production app. The table indicates the minimum length, if it requires at least one upper, lower, digit or special character.
| Expression | Len | Upper | Lower | Digit | Special |
| ^.*(?=.{10,})(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=]).*$ | 10 | Y | Y | Y | Y |
| ^.*(?=.{8,})(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).*$ | 8 | Y | Y | Y | N |
| ^.*(?=.{10,})(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=]).*$ | 10 | Y | Y | Y | Y |
