QR-Code

The QR Code ( Quick Response English, " quick response " as a trademark term " QR code" ) is a two dimensional code, developed by the Japanese company Denso Wave in 1994. Further developments are the Micro QR Code, the Secure QR code ( SQRC ) and the IQR code.

  • 8.1 converting the text into a sequence of bits 8.1.1 example

Basics

The QR code was developed for the marking of assemblies and components for logistics in the automotive production of the Toyota Group. The QR code developing company Denso cooperated already as suppliers, among others for all electrical and electronic components with Toyota. The development of 2D codes took over the subsidiary Denso Wave, the developed identification systems and devices for mobile data collection.

The QR code is a square matrix of black and white dots, representing the binary encoded data. A specific mark in three of the four corners of the square provides its orientation. The data in the QR code are protected by an error-correcting code. Characterized the loss of up to 30 % of the code will be tolerated, i.e., it can also then decoded.

Standards

There are several standards that describe the coding of the QR code.

  • October 1997 - AIM ( Association for Automatic Identification and Mobility ) International
  • January 1999 - JIS X 0510
  • June 2000 - ISO / IEC 18004:2000 (withdrawn) Defines QR Code Model 1 and QR Code model 2
  • November 2004 - Extension of the JIS X 0510 for Micro QR Code
  • 1 September 2006 - ISO / IEC 18004:2006 Defines QR code 2005, an extension of QR code model 2 Specifies not to be read as QR Code Model 1, and builds on QR Code Model 1 specifications.

The QR Code is registered in the following countries as a national standard:

Away from the official standards NTT DoCoMo De facto standards has defined for the encoding of URLs, contact information and other data types. The open source project " ZXing " maintains a list of QR code data types.

Construction

Are included in the code version information (1) and the used data format ( 2). The data portion (3) includes the coded data in redundant form. For the area limitation of the QR- code contains a specific pattern (4.1) in only three of its corners. About the missing pattern in the fourth corner, the reader detects the orientation. With increasing size of the code further samples (4.2 ) can be added to make the alignment of the code easier to see. There is a line (4.3) of a sequence strictly alternating bits, what is the matrix defined between the three main position markers.

Capacity and fault tolerance

The symbol elements are squares, of which at least 21 × 21 and a maximum of 177 × 177 elements are in the symbol. The edge zone ( quiet zone ) should be at least 4 elements wide. Larger content can be split to up to 16 individual codes.

There are four error correction levels, the reconstruction of 7 % ( Level L ) to 30 % ( Level H) tolerate corrupt data. The error correction of the Reed-Solomon coding is used. This property is exploited in the creation of so-called " design codes " (see section: Design QR Code ).

The maximum information content of a QR code (177 × 177 elements, error correction level "L") is 23,648 bits ( 2,953 bytes). This can be according to the manufacturer 7,089 decimal digits, encode 4,296 alphanumeric characters or 1,817 Kanji-/Kana-Zeichen.

The Micro QR -Code with a size between 11 × 11 and 17 × 17 elements takes up to 35 digits on, at a border width of at least two elements.

License

The use of QR codes is license- free. The specifications have been disclosed by Denso Wave and are available through the International Organization for Standardization in Switzerland. The name " QR code" is the United States of America, Australia and Europe especially protected in Japan as a registered trademark of Denso Wave Incorporated. An appropriate notice should be in use.

The QR code is established as a public standard. In Japan it is very common, you can find him there on almost every billboard. The Japanese government used the QR code. For example, using the Japanese immigration authorities the QR code with encrypted data for the visa, which is glued on entry into the passport.

Representation

The QR code can be printed with all standard process without any problems. As with the bar code, however, a very high contrast is also important here, ideally in black and white. Depending on the capabilities of the reading device also used an inverse display is possible. It is also possible for the code to print in color, even with multiple colors or as negative ( " white on black "). However, care must be taken, seen as halftone image or as a line of code that has a uniform contrast. The QR code is being used increasingly applied also in the so-called "Direct Marking " procedure on products. They are baked, for example, with a laser directly on the surface of the characterizing material. These QR codes can be very small and are very durable.

In the view size to the QR code is no limit, as long as the reader can absorb panning and differentiated. We have already provided all the billboards and facades with a single QR code.

Reading codes

Mobile phones

Many mobile phones and PDAs are equipped with a built-in camera and a software that allows you to interpret QR codes. The unit is called mobile tagging process is extremely popular in Japan. It spreads since 2007 and in Europe.

Widespread is the coded picture of a web address, used in magazines, newsletters or large format on billboards. The advantage of this method is that the tedious typing. In addition to URLs contain QR codes in practice, such as phone numbers, addresses, informational text, premium SMS, vCards, Wi-Fi access data or spatial data.

The first QR Code in Germany was on October 16, 2007 by - published on the front page " Spex magazine for pop culture ." The heading " What this tells us that code? " Opened an article that deals with the trend of 2D codes and how they work. The author refers to the code as a sign of our times, as the QR code is used both by the fashion industry as well as the music and video industry.

On 9 November 2007, the printed world leading compact as a first newspaper QR codes. In the meantime, you can see the QR code in many other newspapers and magazines.

Scanner

"Scanner" is analogous to barcode readers of the conventional term for the readers. Industry is also customary, the term " Imager " if it is a 2D device. You have a camera and a decoder. Additionally, many devices offer an aiming aid, often in the form of a laser-generated pattern, which indicates the reading field.

Special readers are able to read QR codes, which have been burned in Direct -marking method with a laser directly on the material. They feature a high-resolution camera and a macro lens as well as special algorithms for eliminating procedural typical display errors.

Generate Codes

To generate a QR code is needed:

  • The text that is to be encoded, and
  • The desired degree of error correction.

The rough process is then:

Converting the text into a sequence of bits

Because of the versatile application possibilities and the small size of QR codes emphasis was placed that the encoded text takes up little space. Depending on which characters appear in the text, you can code the text with different character sets:

  • If the text is all digits (0-9 ), it consumes the least amount of space. In this case, three numbers will be combined and stored as a 10 -bit unit.
  • If the text only of digits (0-9 ), uppercase letters ( AZ) and nine other set of characters, two characters are combined and stored as 11 -bit unit.
  • If the text contains only those characters which appear in ISO -8859-1 (which include uppercase and lowercase letters, numerals, punctuation and combined letters for the Western European languages ​​), each character is stored as an 8- bit unit.
  • If the text consists only of Kanji, each character is stored as a 13 -bit unit.
  • In the remaining cases, it is more complicated; then then the ECI character encoding is hard.

After the appropriate character set is determined, the following information is written to the bit sequence:

Example

To encode the text " storybook ", the matching symbol set is selected first. In this case, the ISO -8859 -1. This character set has the identification number 0100.

In the second step is counted as the number of characters includes the text. In this case, the 11 characters. For small QR codes this number is coded at 8 bits, that is 0000 1011. Larger QR codes, the number would be coded with 16 bits.

Subsequently, the individual characters are encoded. In the case of the encoding ISO -8859-1 you look in the table for the character set according to what number has this character, and writes off the number. For the " M" which is 0100 1101. The "ä" gets the number 1110 0100, and so on.

The conclusion is the end code. She is always 0000 unless more is not enough space. They will be abbreviated.

Overall, from the text " storybook " so this bit sequence:

  • 0100
  • 0000 1011
  • 0100 1101 1110 0100 0111 0010 0110 0011 0110 1000 0110 0101 0110 1110 0110 0010 0111 0101 0110 0011 0110 1000
  • 0000

Divided into 8- bit units, and, if applicable. Fill codes: 01000000 10110100 11011110 01000111 00100110 00110110 10000110 01010110 11100110 00100111 01010110 00110110 10000000 11101100 00010001 11101100 00010001 ...

Applications

In addition to its original purpose, to use in the production logistics and more QR codes are now finding in numerous other applications again: for example, as timetable information and navigation aid at stops of public transport, as an aid to the shopping list, to mark pets or as a mobile business card. Also keep in advertising QR codes continues to feed, can be so fast but additional information, call example, product videos or sites with or without a sweepstakes or link directly to the App Store with the ability to download programs. In the field of museums in Canada, the codes are used to give visitors the ability to invoke accessible via the internet information on individual exhibits or themes. 2012 was first published in an interactive First Day Cover with stamp series "brand individually " a Leipzig merchant shipping. The printed on the letter QR code is used here as a shop access. Even in so-called screen transfers, which involves the transfer of a web page in the Web browser on a device to another, help QR codes.

In the game Munzee the QR codes and GPS coordinates are (GPS - enabled smartphone provided ) as " location-based game" to get on your account when scanning the QR code points. The QR- codes are generated on the gaming platform and distributed in the real world.

A team of researchers from the State of South Dakota has developed a special invisible ink which consists of a mixture of blue and green fluorescent ink with nanoparticles and is under a special laser, similar to infrared light, visible. QR codes, which are printed with this ink on bills or other securities could increase their security against counterfeiting.

Hoarding with QR code

Interactive Stamp with QR code

Our Father, Prayer in the QR code

Hazards

Because the content of a QR code is not apparent at first glance, it is possible to hide in it a link that leads the viewer after scanning to a malicious page or even unintentionally performs functions of its smartphones. However, this applies to all common 2D codes, which are used to encode URLs, and is not a special characteristic of the QR code.

An about such codes ( " tags") applied attack is referred to commonly as " Atagging ". In early September 2010, attacks on mobile phones with Android operating system is known in which could be downloaded through an encrypted into a QR code link to a website of the ICQ client " Jimm ". The software was infected with the Trojan Trojan- SMS.AndroidOS.Jifake.f and sent several unsolicited chargeable SMS to a Russian premium service. The Federal Office for Security in Information Technology warned in early January 2013 taped QR codes on billboards, which could lead the user to rogue websites.

To protect against attacks will initially only appear in many current scanners decoded QR code content, instead of executing it immediately, for example following a link display a page. However, still many QR code scanner load on the mere display the Links page before calling the browser in advance, eg short time after scanning display or speed up the display, which is why a certain risk potential exists even without direct page view, if the scanning software when generating the preview is vulnerable the page title before the actual call.

By manipulating the encoding for the exact number of characters contained in the QR code is to cause in theory the possibility of a buffer underrun or buffer overflow in poorly programmed decoder software. Also, attacks SQL injection would be conceivable, if the processing software has no corresponding protection mechanisms.

A potential danger is at most from the application software you are using, which processes the read data, but not the QR code itself is also of users, especially of mobile phones, contributes to a high degree by inexperienced dealing with encrypted in QR Codes URLs for risk with. Take all the risks mentioned in the same degree for all 2D code systems from other manufacturers. By using the Secure QR- code, most sources of danger in professional applications can be largely eliminated.

Developments

Design QR Code

QR codes can be graphically designed with words, logo or picture and individualized through color shifts or with more effort. Through skilful action and utilization of error correction, the function remains the same. Such QR codes are often referred to as a design QR codes or more elaborate design as custom QR codes. Often alienated QR codes are also known as IQR code, but this is factually incorrect because the IQR code is a separate advanced variant of the QR code.

Design QR codes are no official development of Denso Wave.

In the early days, the design is often limited to a simple exchange of colors. In addition, a logo or a logo can also be as small pixel graphics in most cases are centered at the QR code or worked into it directly.

A part of the data of the code from the graphic is simply superimposed. The redundancy of error correction in the level "H", this enables an area of ​​up to 30% of the whole code. Technically, the data part of a design QR codes by the overlaid graphics controller is disturbed to the extent that it does not provide further redundancy more.

Another possibility is, by mathematical methods, a graphic to be included in a QR code, so that the QR code is error-free.

By linking these processes can be generated today complex custom QR codes in which the design is in the foreground. So QR codes are specifically adapted to existing corporate design or integrated into marketing campaigns. Examples are ads that are dominated by a single, elaborate custom QR code, or company logos that are designed directly as a custom QR codes. 2009 Takashi Murakami designed such corporate QR Code on behalf of Louis Vuitton.

Micro QR Code

The Micro QR Code has been optimized to smallest dimension variant of the QR code. It was introduced in 2000 by Denso Wave. Instead of the familiar three orientation markers of the QR code of the Micro QR Code has only one in the upper left corner. More than 35 digits or 21 alphanumeric characters can be coded, but this less space is required.

The following table contains information on the maximum capacity for each release and appropriate level of error correction:

The Micro QR Code is standardized as JIS X 0510 (November 2004).

Secure - QR Code

The Secure - QR Code ( SQRC ) is a QR code with extended function to encrypt data content. Denso Wave set him before 2005. Use is the SQRC in applications where data content or parts thereof should not be viewed by third parties. For the SQRC provides the ability to encrypt all of the contents or, alternatively, only a part of the data contained. The public ( unencrypted ) data in a SQRC can then be read with normal QR- code readers and mobile phones, while the encrypted information remains hidden. In order to read the encrypted data, it requires a reader that can decode SECURE QR codes. The matching key must be stored in the reader.

The encryption of the data is already taking place in the generation of the SQRC. Decryption is part of the decoder in the reader. An additional encryption software at the application level is therefore not required. To encrypt or decrypt a symmetric key (password ) is required with a length of 16 bytes. The algorithm provides an equivalent security to single DES with 56 bit, but not identical with it.

IQR Code

The IQR code Denso Wave attacks as the current development of the normal QR code on some advantages of Micro QR Code and exceeds in the result so that the properties of the normal QR code. As a novelty, it is not necessarily set to the square shape but may also take the rectangle. This facilitates, for example, the reading of cylindrical objects and integration into applications in which a classical barcode is to be replaced by a 2D code on the medium but not necessarily accommodate a square is present. Are also in demand for applications in which very small codes with maximum possible amounts of data, so extremely compact code, IQR Code offers a solution.

The maximum amount of data was increased 422 elements by around 80 % from 177 × 177 to 422 × elements. So in the largest format (version 61) to accommodate more than 40,000 numeric characters into a single code.

As a rectangle are 15 sizes of 5 × 19 × 43 elements to 131 elements. In the largest format (version R15) can accommodate up to 1,202 numeric characters space.

In addition, the IQR code is up to 30 % less than a standard QR code having the same encoded data. It is also more compact than the micro again QR code. The smallest possible format (version 1) 9 × 9 elements and can accommodate 6 characters.

Due to the supported character encoding of the content according to ISO / IEC 15434 ( transfer syntax ) is possible. This is the use of many possible industrial and commercial common data structures, such as UN / EDIFACT segments, GS1 Application Identifier or ANS MH10.8.2 Data Identifier in accordance with ISO / IEC 15418th

For an increased fault tolerance, in addition, the level "T" is created which allows the recovery of up to 60 % of destroyed data.

The manufacturer Denso Wave plans to the disclosure of the specification and the free use by everyone as Public Domain in full respect of the trademark as already for the QR code. In addition, the registration as an ISO standard is sought.

The Internet to create QR codes (so-called " design QR codes ", also colored and with integrated logo) often referred to as IQR code, but this is factually incorrect.

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