![]() While such an attack requires a flaw in the website you are visiting, such vulnerabilities are common on the internet. The URL could take you to a legitimate website and trick that website into doing something harmful, such as giving an attacker access to your account. The QR code’s URL can take you to a phishing website that tries to trick you into entering your username or password for another website. However, just as it can be hazardous to click links in emails, visiting URLs stored in QR codes can also be risky in several ways. However, due to the QR code’s redundancy, the data represented by these missing dots can be recovered by looking at the remaining visible dots. In fact, logos are not actually part of the QR code they cover up some of the QR code’s data. Even if as much as 30% of the QR code is destroyed or difficult to read, the data can still be recovered. Like barcodes, QR codes are designed with data redundancy. QR codes can include an optional logo in the middle. QR codes are surrounded by blank space, the quiet zone, to help the computer determine where the QR code begins and ends. These markers let a smartphone camera or other device orient the QR code when scanning it. Position markers are squares placed in a QR code’s top-left, top-right, and bottom-left corners. However, this is not a strict requirement, and QR codes can use any color or shape for the dots and background. In most cases, QR codes use black squares on a white background, making the dots easy to distinguish. At its smallest this grid is 21 rows by 21 columns, and at its largest it is 177 rows by 177 columns. ![]() Each dot represents a one and each blank a zero in binary code, and the patterns encode sets of numbers, letters or both, including URLs. The data in a QR code is a series of dots in a square grid. The QR code anatomy: data (1), position markers (2), quiet zone (3) and optional logos (4). QR codes are composed of several parts: data, position markers, quiet zone and optional logos. Tap it, and your phone’s default browser will open the webpage. If the QR code holds a URL, your phone will present you with the URL. When you scan a QR code, the QR reader in your phone’s camera deciphers the code, and the resulting information triggers an action on your phone. QR codes are most often used to store web links however, they can store arbitrary data, such as text or images. QR code scanning is built into many camera apps for Android and iOS. QR codes are designed to be scanned using a camera, such as those found on your smartphone. Even if part of the bar code is destroyed or obscured, it is still possible for a device to read the product ID. Critically, data stored in bar codes is redundant. At the store, bar codes record the set of numbers that specify a product’s ID. Bar codes encode alphanumeric data as a series of black and white lines of various widths. While it is easy for people to read Arabic numerals, it is hard for a computer. ![]() That extra amount of data is what makes QR codes so versatile. ![]() QR codes store information in both vertical and horizontal axes, which allows them to hold significantly more data. Bar codes store information along one axis, horizontally. ![]()
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