I have a card number as a string, for example:
string ClsCommon.str_CardNumbe r = "3456123434561234";
The length of this card number can vary from 16 to 19 digits, depending on the requirement.
My requirement is that I have to show the first six digits and the last 4 digits of a card number and mask the other characters in between with the character 'X'.
I have tried using subString and implemented it separately for 16,17,18,19 digits..
I split string(ClsCommon.str_CardNumber) to 5 strings (str_cardNum1, str_cardNum2, str_cardNum3, str_cardNum4, str_cardNum5 - 4 digits for each string..remaining digits for 5th string)
All the strings are placed in ClsCommon file. Based on that I implemented the below, which works perfectly:
if (ClsCommon.str_CardNumber.Length == 16) {
txtmskcrdnum.Text = string.Concat(ClsCommon.str_cardNum1, " ", ClsCommon.str_cardNum2.Substring(0, 2), "XX", " ", "XXXX", " ", ClsCommon.str_cardNum4);
}
if (ClsCommon.str_CardNumber.Length == 17) {
txtmskcrdnum.Text = string.Concat(ClsCommon.str_cardNum1, " ", ClsCommon.str_cardNum2.Substring(0, 2), "XX", " ", "XXXX", " ", "X", ClsCommon.str_cardNum4.Substring(1, 3), " ", ClsCommon.str_cardNum5);
}
if (ClsCommon.str_CardNumber.Length == 18) {
txtmskcrdnum.Text = string.Concat(ClsCommon.str_cardNum1, " ", ClsCommon.str_cardNum2.Substring(0, 2), "XX", " ", "XXXX", " ", "XX", ClsCommon.str_cardNum4.Substring(2, 2), " ", ClsCommon.str_cardNum5);
}
if (ClsCommon.str_CardNumber.Length == 19) {
txtmskcrdnum.Text = string.Concat(ClsCommon.str_cardNum1, " ", ClsCommon.str_cardNum2.Substring(0, 2), "XX", " ", "XXXX", " ", "XXX", ClsCommon.str_cardNum4.Substring(3, 1), " ", ClsCommon.str_cardNum5);
}
txtmskcrdnum.Text = ClsCommon.str_CardNumber.PadLeft(ClsCommon.str_CardNumber.Length, 'X').Substring(ClsCommon.str_CardNumber.Length - 4);
For multiple lengths, the above approach is not useful.
I want a single approach which displays the first 6 and last 4 digits and masks other digits with X. The final string should have a space between every 4 digits.
This will work with any card number length:
var cardNumber = "3456123434561234";
var firstDigits = cardNumber.Substring(0, 6);
var lastDigits = cardNumber.Substring(cardNumber.Length - 4, 4);
var requiredMask = new String('X', cardNumber.Length - firstDigits.Length - lastDigits.Length);
var maskedString = string.Concat(firstDigits, requiredMask, lastDigits);
var maskedCardNumberWithSpaces = Regex.Replace(maskedString, ".{4}", "$0 ");
Try this one. Simple and straight forward.
public static class StringExtensions
{
public static string Masked(this string source, int start, int count)
{
return source.Masked('x', start, count);
}
public static string Masked(this string source, char maskValue, int start, int count)
{
var firstPart = source.Substring(0, start);
var lastPart = source.Substring(start + count);
var middlePart = new string(maskValue, count);
return firstPart + middlePart + lastPart;
}
}
I would do something like this (pseudo C# - take as rough idea to build upon).
Untested code ahead...
string MaskDigits(string input)
{
//take first 6 characters
string firstPart = input.Substring(0, 6);
//take last 4 characters
int len = input.Length;
string lastPart = input.Substring(len - 4, 4);
//take the middle part (XXXXXXXXX)
int middlePartLenght = input.Substring(6, len - 4).Count();
string middlePart = new String('X', 5);
return firstPart + middlePart + lastPart;
}