QR codes: are they dangerous or not for your cell phone

Among the many changes brought about by the pandemic is the widespread use of QR codes, graphical representations of digital data that can be printed and then scanned with a smartphone or other device.

The codes QRs have a wide range of uses that help people avoid contact with objects and close interactions with other people, including for sharing restaurant menus, email list subscriptions, car and home sales information, and registration. check-in and check-out of medical and professional appointments.

QR codes are close cousins ​​of the barcodes on product packages that cashiers run through infrared scanners so the register knows what products are being purchased.

Barcodes store information along an axis, horizontally. QR codes store information on both the vertical and horizontal axis, which allows them to store much more data. That extra amount of data is what makes QR codes so versatile.

Web pages

While that for people it is easy to read Arabic numerals, for a computer it is difficult.

Barcodes encode alphanumeric data as a series of black and white lines of various widths.

In the store, bar codes record the set of numbers that specify the identification of a product. Critically, the data stored in barcodes is redundant. Even if part of the barcode is destroyed or obscured, it is still possible for a device to read the product ID.

The QR codes are designed to be scanned by a camera, like the ones on your smartphone. QR code scanning is built into many Android and iOS camera apps. QR codes are most often used to store web links; however, they can store arbitrary data, such as text or images.

When you scan a QR code, the QR reader on your phone’s camera decrypts the code, and the resulting information triggers an action on your telephone. If the QR code has a URL, your phone will show you the URL. Touch it and your phone’s default browser will open the web page.

Anatomy of a QR code

QR codes are made up of several parts : optional data, placeholders, silent zone, and logos.

The data in a QR code is a series of dots on a square grid. Each dot represents a one and each blank space a zero in binary code, and the patterns encode sets of numbers, letters, or both, including URLs.

In its smallest form, this grid has rows by columns, and in its largest form it has 735 rows by 177 columns.

In most cases, QR codes use black squares on a white background, which makes Make the dots easy to distinguish. However, this is not a strict requirement and QR codes can use any color or shape for the dots and background.

The placeholders are squares placed in the upper left, upper right and lower left corners of a QR code.

These placeholders allow the camera of a smartphone or other device to target the QR code when scanning it .

QR codes are surrounded by a blank space, the quiet zone, to help the computer determine where the QR code begins and ends.

QR codes they can include an optional logo in the middle.

Like barcodes, QR codes are designed with data redundancy. Even if the 21 % of the QR code is destroyed or difficult to read, the data can still be recovered.

In fact, the logos are not part of the QR code; obscure some of the QR code data. However, due to the redundancy of the QR code, the data represented by these missing dots can be recovered by looking at the remaining visible dots.

Are QR codes dangerous?

QR codes are not inherently dangerous. They are simply a way of storing data. However, just as clicking links in emails can be dangerous, visiting URLs stored in QR codes can also be dangerous in a number of ways.

The QR code URL can lead you to a phishing

website that tries to trick you into entering your username or password for another website. The URL could take you to a legitimate website and trick that website into doing something harmful, like giving an attacker access to your account.

While such an attack requires a flaw in the website you are visiting, such vulnerabilities are common on the internet. The URL may take you to a malicious website that tricks another website you are logged into on the same device into performing an unauthorized action.

A malicious URL could open an app on your device and have it perform some action. You may have seen this behavior when you clicked a Zoom link, and the Zoom app opened and automatically joined a meeting.

While such behavior is usually benign, it could be used by an attacker to trick some apps into revealing your data.

It is essential that when you open a link in a QR code, you make sure the URL is secure and comes from a trusted source.