email address hiding some characters with c#, regex

Question

I would like replace some the chars of the e-mail addresses with * char.

when a customer make request, I would like to hide some the chars of the e-mail addres like below;

ha~~~~@~~~~ail.com

I would like to do that like that. I would like to show first two chars before @ and last 3 chars after @

but is there any other common way of doing this?

You could do a OnKeyDown and store the email in a string somewhere, then tell the textbox to replace the character with whatever you want ~ — Spidy, Feb 24 '11 at 16:24

score 11 · Accepted Answer · answered Feb 24 '11 at 16:46

Similar to other responses, but also different. Accepts the .co.uk addresses too.

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

public class Test
{
        public static void Main()
        {
                String regex = @"(.{2}).+@.+(.{2}(?:\..{2,3}){1,2})";
                String replace = "$1*@*$2";
                List<String> tests = new List<String>(new String[]{
                        "joe@example.com",
                        "jim@bob.com",
                        "susie.snowflake@heretoday.co.uk",
                        "j@b.us",
                        "bc@nh.us"
                });
                tests.ForEach(email =>
                {
                        Console.WriteLine(Regex.Replace(email, regex, replace));
                });
        }
}

Results in:

jo*@*le.com
ji*@*ob.com
su*@*co.uk
j@b.us
bc@nh.us

Though I'm not 100% sure what you want to do with names that only have 2 letters on either side (thus the last two results). But that's my bid. Example

how we could detect that there are more 2 letter on either side so that we could proceed the other way? — tugberk, Feb 25 '11 at 15:41
@tugberk_ugurlu_: note sure I understand what you mean, can you be more specific? — Brad Christie, Mar 05 '11 at 15:02

Fishcake · Answer 2 · 2011-02-24T16:45:56.097

3

Because your rules are quite simple it might be easier to just use substring to get the characters before and after the @ and then replace them.

Something along the lines of

            int index = email.IndexOf('@');                
            string returnValue = email.Replace(email.Substring(index - 3, 3), "***").Replace(email.Substring(index+1,3), "***");

Although you'll need to first validate that the email address contains enough characters before the @ and change accordingly.

edited Feb 24 '11 at 16:45

answered Feb 24 '11 at 16:24

Fishcake

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However I like the regex methods in Tim's answer. I'm just rubbish at building my own regex. – Fishcake Feb 24 '11 at 16:49

score 0 · Answer 3 · answered Jul 31 '15 at 11:54

public static string MaskEmailID(string EmailID)
    {
        MailAddress addr = new MailAddress(EmailID);
        string username = addr.User;
        string domain = addr.Host;
        String regex;
        if (domain.Contains(".com"))
        {
            regex = @"(.{1}).+(.{1})+@(.{1}).+(.{1}(?:\..{2,3}){1,2})";
        }
        else
        {
            regex = @"(.{1}).+(.{1})+@(.{1}).+(.{4}(?:\..{2,3}){1,2})";
        }
        string CharStr1 = new String('*', username.Length - 2);
        string CharStr2 = new String('*', (domain.IndexOf('.') - 2));
        String replace = "$1" + CharStr1 + "$2@$3" + CharStr2 + "$4";
        return Regex.Replace(EmailID, regex, replace);
    }

Thanks for your answer! Please include an explanation with your code. — kittykittybangbang, Jul 31 '15 at 12:20

score 0 · Answer 4 · answered Feb 24 '11 at 16:23

0

You could do this:

resultString = Regex.Replace(subjectString, "([^@]{2})[^@]*@[^.]*([^.]{3}.*)$", "$1~~~@~~~$2");

This will fail, though, if there are less than three characters after the @ (like in tim@me.com), or less than 2 before the @. What would you want to happen in a case like that?

answered Feb 24 '11 at 16:23

Tim Pietzcker

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so if my address were `jim@to.com`, this would give `~~~@~~~com`? – Jim Mischel Feb 24 '11 at 16:30
Slightly different variation, same replacer pattern though: `(.{2}).*@.*(.{2}(?:\..{2,3}){1,2})` -- IDEOne Link: http://www.ideone.com/fvIkr – Brad Christie Feb 24 '11 at 16:34
if there are less than three characters after the @ (like in tim@me.com), or less than 2 before the @, I would like to hide first char. how can I check if there are less than three characters after the @ (like in tim@me.com), or less than 2 before the @? so that I could implement which regex replace I want – tugberk Feb 25 '11 at 15:49

email address hiding some characters with c#, regex

4 Answers4