Regular Expression for password validation

^.*(?=.{8,})(?=.*[a-zA-Z])(?=.*\d)(?=.*[!#$%&? "]).*$

---

^.*              : Start
(?=.{8,})        : Length
(?=.*[a-zA-Z])   : Letters
(?=.*\d)         : Digits
(?=.*[!#$%&? "]) : Special characters
.*$              : End