Luhn Algorithm also known as ‘modulus 10’ or ‘mod 10’ algorithm, was created by Hans Peter Luhn in 1954.
It is widely used in Credit/Debit card numbers, IMEI numbers, and Canadian Social Insurance numbers.
What is Luhn Algorithm?
To understand what Luhn algorithm is, we first need to understand what is ‘modulo’. Modulo or Modulus is the remainder after dividing the number with another number. Consider the example 7 divided by 3 has; quotient 2 and remainder 1.
Therefore, modulo 10 equal 0 means after dividing the number with 10, the remainder should be 0. In simple terms the number (dividend) should be a multiple of 10 (divisor).
In my previous article Auditing: Accounts Payable / Vendor Payments I spoke about Relative Size Factor (RSF) and how it can used to identify isolated outliers in vendor invoices. In this article I’ll try to show how RSF can be calculated in Excel.
The RSF test is an important tool for detecting errors. RSF test compares the top two amounts for each subset and calculates the RSF for each. The test identifies subsets where the largest amount is out of line with other amounts for that subset.
In the previous post I mentioned few of the risks associated with spreadsheets. In this post I’ll try to show some excel tools which can help in detecting errors and frauds in Excel spreadsheets.
In the late 1990’s “Poor control over spreadsheets at Jamaican indigenous banks contributed to management information and external reporting problems (i.e., P&L distortions) that contributed to the banks’ management and external regulators losing sight of the banks’ true positions and exposures. Which led to collapse of entire Jamaican Banking System.
Accounts Payable is one of the crucial area in audit. As it represents the monies owed by the organization to its creditors for supply of goods and services. Also for a fraudster who is looking to steal from the business, accounts payable is an easy target, if proper controls are not there.