Password regex for specific requirements

Question

I am to write a regex for following requirements

1. At least one character
2. At least one digit
3. Length must be of 8
4. At least one special char

Answer 1

You can solve these with a combination of lookaheads:

1. (?=.*[a-zA-Z])
2. (?=.*\d)
3. .{8}
4. (?=.*[^\da-zA-Z])

The last one just requires a non-letter and non-digit which is probably by far the easiest way of specifying that you want a somewhat “special” character.

So in the end you have

^(?=.*[a-zA-Z])(?=.*\d)(?=.*[^\da-zA-Z]).{8}$