regular expression for password in probabilities

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hi

I have a requirement for the password to take any of the three options from four like.......
password must use a combination of at least three of the following four character types:
I.Atleast 1 upper case letters (A – Z)
II.Lower case letters (a – z)
III.Atleast 1 number (0 – 9)
IV.Atleast 1 non-alphanumeric symbol (e.g. @ ‘$%£!’)

So can anyone help me with the regular expression to be given in regular expression validator in asp.net or any other way where i can validate it?

Posted 13-Mar-12 21:41pm

qwerty 2

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3 solutions

Solution 1

A regex is a bad way to do this - this isn't a string matching operation, it's a character counting operation, and regexes are not good at that at all.
Do it in code: loop through each character and count it's groups. You can do this either server side as part of the postback testing or client side as part of the validator - it's up to you.

Posted 13-Mar-12 22:02pm

OriginalGriff

Solution 2

You should use a custom validater for this and not the regex validater. have a custom validater and validate it on client side to improve responsiveness(immediate feedback on wrong format) and validate it on server side to maintain security.

Posted 13-Mar-12 22:16pm

Rahul Rajat Singh

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**tanweer** · Accepted Answer · 2012-03-13T22:42:00

Hi,
it seems that it should implement on server side so call this method on your Button click:

C#

 bool ValidatePassword()
{
    string pass = txtpass.Text;

    bool result = false;
    bool isDigit = false;
    bool isLetter=false;
    bool isLowerChar = false;
    bool isUpperChar = false;
    bool isNonAlpha = false;

    foreach (char c in pass)
    {           
        if (char.IsDigit(c))
            isDigit = true;
        if (char.IsLetter(c))
        {
            isLetter=true;
            if (char.IsLower(c))
                isLowerChar = true;
            if (char.IsUpper(c))
                isUpperChar = true;
        } 
        Match m = Regex.Match(c.ToString(), @"\W|_");
        if (m.Success)
            isNonAlpha = true;
    }

    if (isDigit && isLetter && isLowerChar && isUpperChar && isNonAlpha)
        result = true;

    return result;
}

hope this will help you.