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How digital transactions can be secured?

A QR code is basically a high-tech bar code. You can point a smart phone's camera at it, scan and decode the message in it. In many cases, the decoded message is a web link to avoid the hassle of typing on a phone keypad.

Tags: QR code, digital, transaction, security

BY Guest author  |  Apr 12, 2017  |  comments ( 0 )  | 
How digital transactions can be secured?

As India moves rapidly toward organised retailing and cashless transactions, quick response (QR) code-based payments are gaining ground by the day. You find those small black and white boxes with jigsaw lines on packings, billboards, movie posters, magazines, websites . . . virtually everywhere. But what are these little magical boxes?

A QR code is basically a high-tech bar code. You can point a smart phone's camera at it, scan and decode the message in it. In many cases, the decoded message is a web link to avoid the hassle of typing on a phone keypad.

Compared to a traditional barcode, a QR code with two dimensions can store many times more data over a much smaller surface area. One does not need expensive hardware to read a QR code. Scanners can be as simple as an app on a phone with a camera and some decoding algorithm.

QR codes increase flexibility, reliability and ease of use. These advantages help reduce the cost of implementation. QR codes allow for real content to be stored and not just identities or references. Even when damaged, there is a chance that that they are still readable.

One can scan them from any angle. Readers don't need to be aligned to their orientation. Structured appending of a QR code means that data can be split over multiple codes which can be combined to reconstruct the original content.

The entire purpose of a QR code is to quickly get data from a printed medium to a digital medium where it can be processed. Compatibility, speed and security are keys to their rising usage. Availability of free scanners on all major smartphone platforms means almost everyone has their own scanner on an internet connected device at all times.

QR codes cannot easily be read with a naked eye, and so they are particularly difficult to  

manipulate. They are split into various sections which are scanned to decode the data. A finder pattern consists of three identical structures located in all corners of a QR code except the bottom right corner.

Each pattern is based on a 3 x 3 matrix of black modules surrounded by white modules that are again surrounded by black modules. The finder patterns enable decoder software to recognise the QR code and determine correct orientation.


The white separators have a width of one pixel and improve recognisability of finder patterns as they separate them from actual data. Alternating black and white modules in a timing pattern enables decoder software to determine width of a single module.

The formation information section consists of 15 bits next to separators and stores information about error correction level of a QR code and a chosen masking pattern. Data is converted into a bit stream and then stored in 8 bit parts (code words) in data section.

Similar to data section, error correction codes are stored in 8 bit long code words in error correction section. Another section consists of empty bits if data and error correction bits cannot be divided into 8 bit code words without remainder. Combined, these sections allow QR codes to be flexible, reliable and robust.

Standard QR codes can hold up to 3Kb of data. Their combination of rows and columns makes a grid of modules (squares). There can be a maximum of 177 rows and 177 columns

– which means the maximum possible number of modules is 31,329. To a naked eye, these are just small squares and mean very little. But the exact arrangement of those modules allows a QR code to encode its data.

This means that unlike traditional barcodes which are one dimensional and use one row of lines, QR codes use two dimensions which allow them to store a lot more data in the same area of space. QR code standards do not allow you to create a QR code with just any combination of rows and columns. There are 40 pre-set sizes that you must select from. These are referred to as versions.

Version 1 QR codes will have 21 rows and 21 columns. Each version after that increases by four rows and four columns. The largest is version 40 which has 177 rows and 177 columns, and results in the 31,329 needed to encode the 3kb of data.

When a QR code is being created, a generator assesses the amount of data you are trying to encode. It determines the version number needed to use. These levels allow a generator to encode a QR code as efficiently as possible.

There are also other less common types of QR codes like micro QR codes which are smaller and hold a lot less data, and iQR codes which allow a lot more rows and columns – therefore more modules and ultimately more data.

The article has been penned down by Vineet Singh, CBO, Mobikwik

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