How do I localize password validation in C#?

Question

I am trying to localize an existing app that has the following logic that tries to validate a password text box. I'm assuming that this will not work with languages with special characters that the user could type in the text box. Am I correct? I don't think that we want to restrict the user from typing non-English-type characters (i.e. arabic, chinese, etc.). Or, is there something I'm not understanding?

Regex ValidHex =
   new Regex("[A-Za-z1234567890_-]+", RegexOptions.IgnoreCase);
if (!ValidHex.IsMatch(e.Text))
{
   e.Handled = true;
}

Answer 1

Don't store passwords!

Hash the password using a cryptographic hashing function and compare that.

Answer 2

Have you tried using \w instead of A-za-z? I'm betting that will get around localization issues.

Answer 3

You can do like this to support unicode characters:

[\p{L}\p{N}_-]+

As a side note: is there any specific reason you need to limit what characters are allowed?