Question

I need strong password validation regex

Special Characters - Not Allowed
Spaces - Not Allowed
Numeric Character - At least one character
At least one Capital Letter 
Minimum and Maximum Length of field - 6 to 12 Characters
Repetitive Characters - Allowed only two repetitive characters

my Regex is ^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?!.*\s)(?=(?:(\w)(?!\1{2}))+).{6,12}$
but it ignores special characters (where to add?)

Please help!

Answer 1

^(?=.*[A-Z])(?=.*\d)(?!.*(.)\1\1)[a-zA-Z0-9@]{6,12}$

• Special Characters – Not Allowed
• Spaces – Not Allowed
• Minimum and Maximum Length of field – 6 to 12 Characters
  Met by [a-zA-Z0-9@]{6,12}
• Numeric Character – At least one character
  Met by positive lookahead (?=.*\d)
• At least one Capital Letter
  Met by positive lookahead (?=.*[A-Z])
• Repetitive Characters – Allowed only two repetitive characters
  I am not sure what you mean by this. The negative lookahead (?!.*(.)\1\1) makes sure that no character is allowed to appear more than two times in a row. Substring aa is okay, aaa is not.
  Make it (?!.*(.+)\1\1) to reject repeated substrings of length more than one (like ababab) or add .* before \1 to reject non-continuous repeated appearances too.