Compute Credit Card Check Digits

Compute Credit Card Check Digits

The last digit in your credit card number is a check digit derived from the other digits using the Luhn Formula as described in ISO/IEC 7812-1:1993. Its primary purpose is to ensure accurate entries of the credit card number during transactions. You can apply the same technique to other applications such as employee numbers or patient numbers. Using check digits for these numbers also ensures more accurate data entries:

 Public Function CheckDigit(strNum As String) As Integer	Dim i As Integer	Dim iEven As Integer	Dim iOdd As Integer	Dim iTotal As Integer	Dim strOneChar As String	Dim iTemp As Integer	' Add digits in even ordinal positions	' starting from rightmost	For i = Len(strNum) - 1 To 2 Step -2		strOneChar = Mid$(strNum, i, 1)		If IsNumeric(strOneChar) Then			iEven = iEven + CInt(strOneChar)		End If	Next i	' Process digits in odd ordinal positions	' starting from rightmost	For i = Len(strNum) To 1 Step -2	strOneChar = Mid$(strNum, i, 1)		If IsNumeric(strOneChar) Then			' Double it			iTemp = CInt(strOneChar) * 2			If iTemp > 9 Then				' Break the digits (e.g., 19 becomes 1+9)				iOdd = iOdd + (iTemp  10) + (iTemp - 10)			Else				iOdd = iOdd + iTemp			End If		End If	Next i	' Add even and odd	iTotal = iEven + iOdd	' Return the 10's complement	CheckDigit = 10 - (iTotal Mod 10)End Function

To test, pass your credit card number, excluding the last digit, as a string parameter. The result should be the last digit of your credit card number.

Share the Post:
Heading photo, Metadata.

What is Metadata?

What is metadata? Well, It’s an odd concept to wrap your head around. Metadata is essentially the secondary layer of data that tracks details about the “regular” data. The regular

XDR solutions

The Benefits of Using XDR Solutions

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several

data fivetran pricing

Fivetran Pricing Explained

One of the biggest trends of the 21st century is the massive surge in analytics. Analytics is the process of utilizing data to drive future decision-making. With so much of

kubernetes logging

Kubernetes Logging: What You Need to Know

Kubernetes from Google is one of the most popular open-source and free container management solutions made to make managing and deploying applications easier. It has a solid architecture that makes

ransomware cyber attack

Why Is Ransomware Such a Major Threat?

One of the most significant cyber threats faced by modern organizations is a ransomware attack. Ransomware attacks have grown in both sophistication and frequency over the past few years, forcing