Title: Credit Card Functions Author: Anthony Main Email: anthony.main@webdynamix.biz Environment: c# Keywords: credit card, validation, luhn, card type, visa, mastercard, solo, switch, maestro Level: Intermediate Description: Various methods for validating credit card details Section .NET SubSection General
Here is my Payment class for doing basic credit/debit card validation checks in c#. Includes the following functions:
The LUHN check was taken from another example, however I do not remember where to give credit please let me know if you
find it elsewhere so I can give credit.
The Card Type lookup is fairly rudamentory. It follows some simple rules as found in Wikipedia
for identifying card type. These are not exhaustive and may not always be valid as there is no defined standard, but they will give
a fairly accurate lookup facility for checking against a user submitted type.
The class contains two static methods which can be called from your routines to aid with your validation, all you need to do is pass in the card number.
public static bool IsLUHNValid(string ccNo)
{
bool isValid = false;
int indicator = 1; // will be indicator for every other number
int firstNumToAdd = 0; // will be used to store sum of first set of numbers
int secondNumToAdd = 0; // will be used to store second set of numbers
string num1; // will be used if every other number added is greater than 10, store the left-most integer here
string num2; // will be used if ever yother number added is greater than 10, store the right-most integer here
// Convert our creditNo string to a char array
char[] ccArr = ccNo.ToCharArray();
if (IsNumeric(ccNo))
{
for (int i=ccArr.Length-1;i>=0;i--)
{
char ccNoAdd = ccArr[i];
int ccAdd = Int32.Parse(ccNoAdd.ToString());
if (indicator == 1)
{
// If we are on the odd number of numbers, add that number to our total
firstNumToAdd += ccAdd;
// set our indicator to 0 so that our code will know to skip to the next piece
indicator = 0;
}
else
{
// if the current integer doubled is greater than 10
// split the sum in to two integers and add them together
// we then add it to our total here
if ((ccAdd + ccAdd) >= 10)
{
int temporary = (ccAdd + ccAdd);
num1 = temporary.ToString().Substring(0,1);
num2 = temporary.ToString().Substring(1,1);
secondNumToAdd += (Convert.ToInt32(num1) + Convert.ToInt32(num2));
}
else
{
// otherwise, just add them together and add them to our total
secondNumToAdd += ccAdd + ccAdd;
}
// set our indicator to 1 so for the next integer we will perform a different set of code
indicator = 1;
}
}
// If the sum of our 2 numbers is divisible by 10, then the card is valid. Otherwise, it is not
if ((firstNumToAdd + secondNumToAdd) % 10 == 0)
{
isValid = true;
}
else
{
isValid = false;
}
}
else
isValid = false;
return isValid;
}
public enum CardType
{
Invalid,
Unknown,
AmericanExpress,
Bankcard,
DinersClubInternational,
DinersClubUSandCanada,
DiscoverCard,
JCB,
Maestro,
MasterCard,
SoloDebit,
SwitchDebit,
Visa,
VisaElectron,
enRoute
}
public static CardType GetCardType(string strCardNumber)
{
strCardNumber = strCardNumber.Replace(" ", "");
// Check American Express
if (strCardNumber.Substring(0, 2)=="34" || strCardNumber.Substring(0, 2)=="37")
{
if (strCardNumber.Length==15)
return CardType.AmericanExpress;
else
return CardType.Invalid;
}
// Check Bankcard
if (strCardNumber.Substring(0, 3).ToUpper == "DNE") return CardType.Bankcard;
// Check Diners Club Internationl
if (strCardNumber.Substring(0, 2).ToUpper == "36" || strCardNumber.Substring(0, 2).ToUpper == "38" || (Convert.ToInt32(strCardNumber.Substring(0, 3)) >= 300 && Convert.ToInt32(strCardNumber.Substring(0, 3)) <= 305))
if (strCardNumber.Length==14)
return CardType.DinersClubInternational;
else
return CardType.Invalid;
// Check Diners Club US and Canadaa
if (strCardNumber.Substring(0, 2).ToUpper == "55") return CardType.DinersClubUSandCanada;
// Check Discover Card
if (strCardNumber.Substring(0, 4).ToUpper == "6011")
if (strCardNumber.Length==16)
return CardType.Bankcard;
else
return CardType.Invalid;
// Check JCB Card
if (strCardNumber.Substring(0, 4).ToUpper == "2131" || trCardNumber.Substring(0, 4).ToUpper == "1800" )
if (strCardNumber.Length==15)
return CardType.JCB;
else
return CardType.Invalid;
// Check Maestro Card
if (strCardNumber.Substring(0, 4).ToUpper == "5020")
if (strCardNumber.Length==16)
return CardType.Maestro;
else
return CardType.Invalid;
// Check MasterCard
if ((Convert.ToInt32(strCardNumber.Substring(0, 3)) >= 51 && Convert.ToInt32(strCardNumber.Substring(0, 3)) <= 55))
if (strCardNumber.Length==16)
return CardType.MasterCard;
else
return CardType.Invalid;
// Check Solo Card
if (strCardNumber.Substring(0, 2).ToUpper == "63" || strCardNumber.Substring(0, 4).ToUpper == "6767")
if (strCardNumber.Length==16 || strCardNumber.Length==18 || strCardNumber.Length==19)
return CardType.SoloDebit;
else
return CardType.Invalid;
// Check Switch Card
if (strCardNumber.Substring(0, 4).ToUpper == "4903" || strCardNumber.Substring(0, 4).ToUpper == "4905" || strCardNumber.Substring(0, 4).ToUpper == "4911" || strCardNumber.Substring(0, 4).ToUpper == "4936" || strCardNumber.Substring(0, 6).ToUpper == "564182" || strCardNumber.Substring(0, 6).ToUpper == "633110" || strCardNumber.Substring(0, 4).ToUpper == "6333" || strCardNumber.Substring(0, 4).ToUpper == "6759")
if (strCardNumber.Length==16 || strCardNumber.Length==18 || strCardNumber.Length==19)
return CardType.SwitchDebit;
else
return CardType.Invalid;
// Check Visa Electron Card
if (strCardNumber.Substring(0, 6).ToUpper == "417500")
if (strCardNumber.Length==16)
return CardType.VisaElectron;
else
return CardType.Invalid;
// Check Visa Card
if (strCardNumber.Substring(0, 1).ToUpper == "4")
if (strCardNumber.Length==16)
return CardType.Visa;
else
return CardType.Invalid;
// Check enRoute Card
if (strCardNumber.Substring(0, 4).ToUpper == "2014" || strCardNumber.Substring(0, 4).ToUpper == "2149")
if (strCardNumber.Length==15)
return CardType.enRoute;
else
return CardType.Invalid;
return CardType.Unknown;
}
}
1.0 - 22 August 2006 - Checks are appropriate to prefixes dicated on Wikipedia on this date