---
title: "How to Configure Detection Patterns"
slug: "configure-detection-patterns"
updated: 2024-02-01T22:40:55Z
published: 2024-02-01T22:40:55Z
canonical: "docs.blackthorn.io/configure-detection-patterns"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blackthorn.io/llms.txt
> Use this file to discover all available pages before exploring further.

# How to Configure Detection Patterns

1. Select the tab “Detection Patterns”. ![Detection Patterns Tab](https://cdn.document360.io/f977eec0-500f-40a3-b663-724a51f78075/Images/Documentation/Detection%20Patterns%20Tab.png)
2. Click on the specific Detection Pattern Name. ![amex](https://cdn.document360.io/f977eec0-500f-40a3-b663-724a51f78075/Images/Documentation/amex.png)
3. If you’re already in the Setup, navigate to: Setup > Custom Code > Custom Metadata Types > DetectionPattern > Manage DetectionPattern.
4. You should see a list of Detection Patterns. Click **Edit** on the Pattern you wish to configure. ![Edit the Pattern](https://cdn.document360.io/f977eec0-500f-40a3-b663-724a51f78075/Images/Documentation/Edit%20the%20Pattern.png)
5. Enter a Pattern. This pattern must be a ***valid*** Regular Expression. Try a free tool like [this](https://regexr.com/) to check whether your regex is valid.
6. Select Mask Character. Enter any single character you want to mask PII numbers with - the default is an asterix (e.g. AMERICANEXPRESS****) but you could use an X, #, @, or any other single character you need.
7. Select Mask Type.
  - "Full Mask": all characters are masked
  - "Last4": all credit card number characters are masked but the last 4 characters (AMERICANEXPRESS****1234)
  - "First6andLast4": all credit card number characters are masked but the first 6 and the last 4 characters (AMERICANEXPRESS123456**1234)
8. If the pattern is for credit card numbers, check the box `LuhnCheck`.
  - When this box is checked, all numbers matching this pattern will go through a Luhn algorithm check for credit card number validity.
  - If this box is unchecked, all numbers matching this pattern will skip the Luhn algorithm.

          What is Luhn algorithm?

          

The Luhn algorithm, also known as the modulus 10 or mod 10 algorithm, is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, Canadian Social Insurance Numbers.

1. Check the box `IsActive`.
2. Press **Save**.

**Tip:** It is recommended that you only store the minimum amount of credit card digits you need to verify customer accounts.