A quick response (QR) code is a two-dimensional barcode that can be read by smartphones with cameras. Originally, QR codes were invented to track auto parts in manufacturing, but they quickly grew into a marketing tool that has now become ubiquitous.
QR codes can contain a lot of information, including URLs, text, contacts, geolocation data, and more. They can also be dynamic, allowing the code to change over time. For example, if a QR code is linked to a midnight sale, the code’s URL may automatically update after the promotional period has ended.
Using a QR code reader app, the user can scan a QR code to display text or links on their phone. Most newer smartphones have a built-in QR code reader; however, users of older phones will need to download a separate app in order to use this feature.
When a QR code is scanned, the software on the scanning device reads the pattern of dots and determines what to do with it. If the code is a link to a website, it will open the web browser and display the site’s content. Depending on what type of QR code is used, other actions can be taken as well: adding contact details to a smartphone address book; downloading an application; sending a tweet; or opening a map of a location.
In addition to URLs, QR codes can contain other types of data such as vCards, plain text, emails, SMS, Twitter and WiFi connection details. The exact data that can be stored is determined by the encoding mode of the QR code, which is specified by four-bit indicators. Each of the indicators corresponds to a different input mode, which can be numeric, alphanumeric, binary or kanji.
Because they can contain such a wide variety of information, QR codes are widely used by marketers for advertising and promotion. They are used on posters, product packaging, billboards and vehicle wraps to instantly direct consumers to a website or mobile application. They can also be used to track products through the supply chain, a practice known as item-level tagging.
While there are a number of advantages to using QR codes, they can also be misused by malicious actors. Hackers can create QR codes that redirect to phishing websites where unsuspecting users could disclose personal or financial information. Attackers can also embed custom malware into a QR code that will exfiltrate data from a mobile device when scanned. As a result, it is crucial to protect against these risks by implementing security measures such as scan tests and secure coding practices.