QR code

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Not to be confused with Quadratic residue code.
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QR code for the URL of the English Wikipedia Mobile main page, "http://en.m.wikipedia.org"
Telephone directory with QR code on the cover

QR code (abbreviated from Quick Response Code) is the trademark for a type of matrix barcode (or two-dimensional bar code) first designed for the automotive industry in Japan. Bar codes are optical machine-readable labels attached to items that record information related to the item. It was initially patented; however, its patent holder has chosen not to exercise those rights[citation needed]. Recently, the QR Code system has become popular outside the automotive industry due to its fast readability and greater storage capacity compared to standard UPC barcodes. The code consists of black modules (square dots) arranged in a square grid on a white background. The information encoded may be made up of four standardized types ("modes") of data (numeric, alphanumeric, byte / binary, Kanji) or, through supported extensions, virtually any type of data.[1]

Contents

[edit] Invention

The QR code was invented in Japan by the Toyota subsidiary Denso Wave in 1994 to track vehicles during manufacture. It was designed to allow high-speed component scanning.[2] It has since become one of the most popular types of two-dimensional barcodes.[3]

Unlike the older one-dimensional barcode that was designed to be mechanically scanned by a narrow beam of light to extract data, the QR code is detected as a 2-dimensional digital image by a semiconductor image sensor and is then digitally analyzed by a programmed processor. The processor locates the three distinctive squares at the corners of the image, and uses a smaller square near the fourth corner to normalize the image for size, orientation, and angle of viewing. The small dots are then converted to binary numbers and their validity checked with an error-correcting code.

[edit] Standards

Structure of a QR code, highlighting functional elements

There are several standards in documents covering the physical encoding of QR codes:[4]

At the application layer, there is some variation between most of the implementations. Japan's NTT DoCoMo has established de facto standards for the encoding of URLs, contact information, and several other data types.[6] The open-source "ZXing" project maintains a list of QR code data types.[7]

[edit] Uses

Originally designed for industrial uses, QR codes have become common in consumer advertising. Smartphone users can install an app with a QR-code scanner that can read a displayed code and convert it to a URL directing the smartphone's browser to the website of a company, store, or product associated with that code providing specific information.

In the shopping industry, knowing what causes the consumers to be motivated when approaching products by the use of QR codes, advertisers and marketers can use the behavior of scanning to get consumers to buy, causing it to have the best impact on ad and marketing design."[8] As a result, the QR code has become a focus of advertising strategy, since it provides quick and effortless access to the brand's website.[9][10] Beyond mere convenience to the consumer, the importance of this capability is that it increases the conversion rate (that is, increases the chance that contact with the advertisement will convert to a sale), by coaxing qualified prospects further down the conversion funnel without any delay or effort, bringing the viewer to the advertiser's site immediately, where a longer and more targeted sales pitch may continue. Although initially used to track parts in vehicle manufacturing, QR codes are now (as of 2012) used over a much wider range of applications, including commercial tracking, entertainment and transport ticketing, product/loyalty marketing (examples: mobile couponing where a company's discounted and percent discount can be captured using a QR code decoder which is a mobile app, or storing a company's information such as address and related information alongside its alpha-numeric text data as can be seen in Yellow Pages directory), and in-store product labeling. It can also be used in storing personal information for use by government. An example of this is Philippines National Bureau of Investigation (NBI) where NBI clearances now come with a QR code. Many of these applications target mobile-phone users (via mobile tagging). Users may receive text, add a vCard contact to their device, open a Uniform Resource Identifier (URI), or compose an e-mail or text message after scanning QR codes. They can generate and print their own QR codes for others to scan and use by visiting one of several pay or free QR code-generating sites or apps. Google has a popular API to generate QR codes,[11] and apps for scanning QR codes can be found on nearly all smartphone devices.[12]

QR codes storing addresses and Uniform Resource Locators (URLs) may appear in magazines, on signs, on buses, on business cards, or on almost any object about which users might need information. Users with a camera phone equipped with the correct reader application can scan the image of the QR code to display text, contact information, connect to a wireless network, or open a web page in the telephone's browser. This act of linking from physical world objects is termed hardlinking or object hyperlinking. QR codes also may be linked to a location to track where a code has been scanned. Either the application that scans the QR code retrieves the geo information by using GPS and cell tower triangulation (aGPS) or the URL encoded in the QR code itself is associated with a location.[13]

QR codes have been used and printed on Chinese train tickets since late 2009[citation needed]

In June 2011, the Royal Dutch Mint (Koninklijke Nederlandse Munt) issued the world's first official coin with a QR code to celebrate the centennial of its current building and premises. The coin was able to be scanned by a smartphone and link to a special website with contents about the historical event and design of the coin.[14] This was the first time a QR code was used on currency.

[edit] Mobile operating systems

QR codes can be used in Google's Android operating system and iOS devices (iPhone/iPod/iPad), as well as by using Google Goggles, 3rd party barcode scanners, and the Nintendo 3DS. The browser supports URI redirection, which allows QR codes to send metadata to existing applications on the device. mbarcode[15] is a QR code reader for the Maemo operating system. In Apple's iOS, a QR code reader is not natively included, but more than fifty paid and free apps are available with both the ability to scan the codes and hard-link to an external URL. Google Goggles is an example of one of many applications that can scan and hard-link URLs for iOS. With BlackBerry devices, the App World application can natively scan QR codes and load any recognized Web URLs on the device's Web browser. Windows Phone 7.5 is able to scan QR codes through the Bing search app.

[edit] URLs

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URLs aided marketing conversion rates even in the pre-smartphone era but during those years faced several limitations: ad viewers usually had to type the URL and often did not have a web browser in front of them at the moment they viewed the ad. The chances were high that they would forget to visit the site later, not bother to type a URL, or forget what URL to type. Friendly URLs decreased these risks but did not eliminate them. Some of these disadvantages to URL conversion rates are fading away now that smartphones are putting web access and voice recognition in constant reach. Thus an advert viewer need only reach for his or her phone and speak the URL, at the moment of ad contact, rather than remember to type it into a PC later.

[edit] Virtual stores

During the month of June 2011, according to one study, 14 million mobile users scanned a QR code or a barcode. Some 58% of those users scanned a QR or bar code from their homes, while 39% scanned from retail stores; 53% of the 14 million users were men between the ages of 18 and 34.[16] The use of QR codes for "virtual store" formats started in South Korea,[17] and Argentina,[18] but is currently expanding globally.[19] Big companies such as Walmart, Procter & Gamble and Woolworths have already adopted the Virtual Store concept.[20]

[edit] Code payments

QR codes can be used to store a bank account information or a credit card information, or they can be specifically designed to work with particular payment provider applications. There are several trial applications of QR code payments across the world.[21][22]

In November 2012, QR code payments were deployed on a larger scale in the Czech Republic when an open format for payment information exchange - a Short Payment Descriptor - was introduced and blessed by the Czech Banking Association as the official local solution for QR payments.[23]

[edit] Design

[edit] Storage

The amount of data that can be stored in the QR code symbol depends on the datatype (mode, or input character set), version (1, …, 40, indicating the overall dimensions of the symbol), and error correction level. The maximum storage capacities occur for 40-L symbols (version 40, error correction level L):[3][24]

Maximum character storage capacity (40-L)
character refers to individual values of the input mode/datatype
Input mode max. characters bits/char possible characters, default encoding
Numeric only 7,089 3⅓ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Alphanumeric 4,296 5½ 0–9, A–Z (upper-case only), space, $, %, *, +, -, ., /, :
Binary/byte 2,953 8 ISO 8859-1
Kanji/kana 1,817 13 Shift JIS X 0208

Here are some sample QR code symbols:

  • Version 1 (21×21). Content: "Ver1"

  • Version 2 (25×25). Content: "Version 2"

  • Version 3 (29×29). Content: "Version 3 QR code"

  • Version 4 (33×33). Content: "Version 4 QR code, up to 50 char"

  • Version 10 (57×57). Content: "Version 10 QR code, up to 174 char at H level, with 57x57 modules and plenty of error correction to go around. Note that there are additional tracking boxes"

  • Version 40 (177×177). Content: "Version 40 QR code can contain up to 1852 chars. (…)" (a total of 1,264 characters of ordinary/ASCII text, taken from an early version of this Wikipedia article)

[edit] Encryption

Japanese visa with a QR code

Encrypted QR codes, which are not very common, have a few implementations. An Android app,[25] for example, manages encryption and decryption of QR codes using the DES algorithm (56 bits).[26] The Japanese immigration system uses encrypted QR codes when issuing visa in passports [27] as shown in the figure here.

[edit] Error correction

Damaged but still decodable QR code
Example of a QR code with artistic embellishment that will still scan correctly thanks to error correction.

Codewords are 8 bits long and use the Reed–Solomon error correction algorithm with four error correction levels. The higher the error correction level, the less storage capacity. The following table lists the approximate error correction capability at each of the four levels:

Level L (Low) 7% of codewords can be restored.
Level M (Medium) 15% of codewords can be restored.
Level Q (Quartile)[28] 25% of codewords can be restored.
Level H (High) 30% of codewords can be restored.

Due to the design of Reed–Solomon codes and the use of 8-bit codewords, an individual code block cannot be more than 255 codewords in length. Since the larger QR symbols contain much more data than that, it is necessary to break the message up into multiple blocks. The QR specification does not use the largest possible block size, though; instead, it defines the block sizes so that no more than 30 error-correction symbols appear in each block. This means that at most 15 errors per block can be corrected, which limits the complexity of certain steps in the decoding algorithm. The code blocks are then interleaved together, making it less likely that localized damage to a QR symbol will overwhelm the capacity of any single block.

Thanks to error correction, it is possible to create artistic QR codes that still scan correctly, but contain intentional errors to make them more readable or attractive to the human eye, as well as to incorporate colors, logos, and other features into the QR code block.[29][30]

[edit] Encoding

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The format information records two things: the error correction level and the mask pattern used for the symbol. Masking is used to break up patterns in the data area that might confuse a scanner, such as large blank areas or misleading features that look like the locator marks. The mask patterns are defined on a grid that is repeated as necessary to cover the whole symbol. Modules corresponding to the dark areas of the mask are inverted. The format information is protected from errors with a BCH code, and two complete copies are included in each QR symbol.

The message data is placed from right to left in a zigzag pattern, as shown below. In larger symbols, this is complicated by the presence of the alignment patterns and the use of multiple interleaved error-correction blocks.

  • Meaning of format information

  • Message placement within a QR symbol

  • Larger symbol illustrating interleaved blocks

Four-bit indicators are used to select the encoding mode and convey other information. Encoding modes can be mixed as needed within a QR symbol.

Encoding modes
Indicator Meaning
0001 Numeric encoding (10 bits per 3 digits)
0010 Alphanumeric encoding (11 bits per 2 characters)
0100 Byte encoding (8 bits per character)
1000 Kanji encoding (13 bits per character)
0011 Structured append (used to split a message across multiple QR symbols)
0111 Extended Channel Interpretation (select alternate character set or encoding)
0101 FNC1 in first position (see Code 128 for more information)
1001 FNC1 in second position
0000 End of message

After every indicator that selects an encoding mode is a length field that tells how many characters are encoded in that mode. The number of bits in the length field depends on the encoding and the symbol version.

Number of bits per length field
Encoding Ver. 1–9 10–26 27–40
Numeric 10 12 14
Alphanumeric 9 11 13
Byte 8 16 16
Kanji 8 10 12

Alphanumeric encoding mode stores a message more compactly than the byte mode can, but cannot store lower-case letters and has only a limited selection of punctuation marks, which are sufficient for most web addresses. Two characters are coded in an 11-bit value by this formula:

V = 45 × C1 + C2
Alphanumeric character codes
Code Character Code Character Code Character Code Character Code Character
00 0 09 9 18 I 27 R 36 SP
01 1 10 A 19 J 28 S 37 $
02 2 11 B 20 K 29 T 38 %
03 3 12 C 21 L 30 U 39 *
04 4 13 D 22 M 31 V 40 +
05 5 14 E 23 N 32 W 41 –
06 6 15 F 24 O 33 X 42 .
07 7 16 G 25 P 34 Y 43 /
08 8 17 H 26 Q 35 Z 44 :

[edit] Decoding example

The following images offer more information about the QR code.

  • 1 — Introduction

  • 2 — Structure

  • 3 — Layout & Encoding

  • 4 — Levels & Masks

  • 5 — Protocols

[edit] License

The use of QR codes is free of any license. The QR code is clearly defined and published as an ISO standard.

Denso Wave owns the patent rights on QR codes, but has chosen not to exercise them.[4] In the USA, the granted QR code patent is US 5726435 , and in Japan JP 2938338 . The European Patent Office granted patent "EPO 0672994". http://worldwide.espacenet.com/publicationDetails/biblio?DB=EPODOC&II=0&ND=3&adjacent=true&locale=en_EP&FT=D&date=19950920&CC=EP&NR=0672994A1&KC=A1. to Denso Wave, which was then validated into French, British, and German patents, all of which are still in force as of November 2011.

The word QR code itself is a registered trademark of Denso Wave Incorporated.[31] In UK, the trademark is registered as E921775, the word "QR Code", with a filing date of 03/09/1998.[32] The UK version of the trademark is based on the Kabushiki Kaisha Denso (DENSO CORPORATION) trademark, filed as Trademark 000921775, the word "QR Code", on 03/09/1998 and registered on 6/12/1999 with the European Union OHIM (Office for Harmonization in the Internal Market).[33] The U.S. Trademark for the word "QR Code" is Trademark 2435991 and was filed on 29 September 1998 with an amended registration date of 13 March 2001, assigned to Denso Corporation.[34]

[edit] Variants

Example of Micro QR

Micro QR code is a smaller version of the QR code standard for applications with less ability to handle large scans. There are different forms of Micro QR codes as well. The highest of these can hold 35 numeric characters.[35]

[edit] Risks

Malicious QR codes combined with a permissive reader can put a computer's contents and user's privacy at risk. This practice is known as "attagging", a portmanteau of "attack tagging".[36] They are easily created and can be affixed over legitimate QR codes.[37] On a smartphone, the reader's permissions may allow use of the camera, full Internet access, read/write contact data, GPS, read browser history, read/write local storage, and global system changes.[38][39][40]

Risks include linking to dangerous web sites with browser exploits, enabling the microphone/camera/GPS, and then streaming those feeds to a remote server, analysis of sensitive data (passwords, files, contacts, transactions),[41] and sending email/SMS/IM messages or DDOS packets as part of a botnet, corrupting privacy settings, stealing identity,[42] and even containing malicious logic themselves such as JavaScript [43] or a virus.[44][45] These actions could occur in the background while the user is only seeing the reader opening a seemingly harmless web page.[46] In Russia, a malicious QR code caused phones that scanned it to send premium texts at a fee of US$6 each.[36]

[edit] See also

[edit] References

  1. ^ "QR Code features". Denso-Wave. Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.qrcode.com/en/qrfeature.html. Retrieved 3 October 2011.
  2. ^ Borko Furht (2011). Handbook of Augmented Reality. Springer. p. 341. http://books.google.com/books?id=fG8JUdrScsYC&lpg=PP1&dq=Handbook%20of%20Augmented%20Reality&pg=PA341.
  3. ^ a b "QR Code — About 2D Code". Denso-Wave. Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.qrcode.com/en/aboutqr.html. Retrieved 3 October 2011.
  4. ^ a b "QR Code Standardization". QR Code.com. Denso-Wave. Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.qrcode.com/en/qrstandard.html. Retrieved 23 April 2009.
  5. ^ "AIM Global Online Store". Aimglobal.org. Archived from the original on 2012-09-15. http://archive.is/20120915/https://www.aimglobal.org/estore/ProductDetails.aspx?ProductID=31. Retrieved 23 April 2009.
  6. ^ "Synchronization with Native Applications". NTT DoCoMo. Archived from the original on 2012-09-05. http://archive.is/20120905/http://www.nttdocomo.co.jp/english/service/imode/make/content/barcode/function/application/. Retrieved 17 February 2009.
  7. ^ "Barcode Contents". zxing – A rough guide to standard encoding of information in barcodes. Archived from the original on 2012-05-30. http://archive.is/20120530/http://code.google.com/p/zxing/wiki/BarcodeContents. Retrieved 17 February 2009.
  8. ^ Tolliver-Walker, Heidi (2011). "Making Best Use of QR codes: Gleaning Lessons from the Latest Data". Seybold Report: Analyzing Publishing Technologies 11 (23): 2–7.
  9. ^ "http://www.mobilemarketer.com/cms/news/software-technology/11930.html". Archived from the original on 2012-09-12. http://archive.is/20120912/http://www.mobilemarketer.com/cms/news/software-technology/11930.html.
  10. ^ "http://blogs.vancouversun.com/2012/01/04/tescos-cool-qr-code-advertising-campaign/". Archived from the original on 2012-07-20. http://archive.is/20120720/http://blogs.vancouversun.com/2012/01/04/tescos-cool-qr-code-advertising-campaign/.
  11. ^ "Google Chart Tools". Archived from the original on 2012-07-07. http://archive.is/20120707/http://code.google.com/apis/chart/infographics/.
  12. ^ "QR Code Readers for iPhone, Android, Blackberry and Windows Phone 7". Archived from the original on 2012-07-18. http://archive.is/20120718/http://www.708media.com/qrcode/qr-code-readers-iphone-android-blackberry-windows-phone-7/.
  13. ^ "Geo Tagged QR Codes". Archived from the original on 2012-07-14. http://archive.is/20120714/http://qrd.by. Retrieved 27 October 2011.
  14. ^ "World's first QR code coin website". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.q5g.nl/.
  15. ^ "package overview for mbarcode". Maemo.org. Archived from the original on 2012-07-11. http://archive.is/20120711/http://maemo.org/packages/view/mbarcode/. Retrieved 28 July 2010.
  16. ^ "16 August 2011". Archived from the original on 2012-09-06. http://archive.is/20120906/http://www.internetretailing.net/2011/08/14m-americans-scanned-qr-and-bar-codes-with-their-mobiles-in-june-2011/.
  17. ^ "Tesco QR Code Virtual Store". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.shop2mobi.com/tesco-qr-code-virtual-store/.
  18. ^ "Marketing futurista: ya se puede comprar con la cámara del celular". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.ieco.clarin.com/empresas/Marketing-futurista-comprar-camara-celular_0_555544518.html.
  19. ^ "11 November 2010". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.physorg.com/news/2010-11-phone-friendly-codes-ads.html.
  20. ^ "Top 10 QR Code Store examples". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.shop2mobi.com/virtual-qr-code-store-examples/.
  21. ^ "SCVNGR Unveils QR Code Payment System". http://mashable.com/2011/10/12/scvngr-levelup-redo/.
  22. ^ "MasterCard starts piloting QkR mobile payment app". http://gigaom.com/2012/01/26/mastercard-starts-piloting-qkr-mobile-payment-app/.
  23. ^ "Standard No. 26: Format for exchanging the payment information for Czech domestic payments using the QR codes". Czech Banking Association. 2012-11. https://www.czech-ba.cz/aktivity/standardy/format-pro-sdileni-platebnich-udaju-v-czk-qr-kody.
  24. ^ "Version and Maximum capacity table". Denso-Wave. Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.qrcode.com/en/vertable1.html.
  25. ^ "QR Droid". Google. 19 August 2011. Archived from the original on 2012-09-15. http://archive.is/20120915/https://market.android.com/details?id=la.droid.qr. Retrieved 5 September 2011.
  26. ^ "Encrypted QR Codes". QR Droid. 24 October 2011. Archived from the original on 2012-07-13. http://archive.is/20120713/http://qrdroid.com/encrypted-qr-codes-share-secret-messages.html. Retrieved 5 September 2011.
  27. ^ "QR Code Usage In Japan". Studio Cliffano. 18 May 2009. Archived from the original on 2012-09-15. http://archive.is/20120915/http://blog.cliffano.com/2009/05/18/qr-code-usage-in-japan/. Retrieved 18 May 2009.
  28. ^ "2D Barcode: QR-Code". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.tec-it.com/de/support/knowbase/symbologies/qrcode/Default.aspx. — TEC-IT
  29. ^ Orli Sharaby (18 October 2010). "Form Meets Function: Extreme Makeover QR Code Edition". Archived from the original on 2012-07-08. http://archive.is/20120708/http://blog.360i.com/emerging-media/creative-qr-codes. Retrieved 29 July 2011.
  30. ^ Hamilton Chan (18 April 2011). "HOW TO: Make Your QR Codes More Beautiful". Archived from the original on 2012-07-10. http://archive.is/20120710/http://mashable.com/2011/04/18/qr-code-design-tips/. Retrieved 29 July 2011.
  31. ^ "QR Code.com". Denso-Wave. 6 November 2003. Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.qrcode.com/en/index.html. Retrieved 23 April 2009.
  32. ^ "UK QR Code Trademark". Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.ipo.gov.uk/types/tm/t-os/t-find/t-find-number?detailsrequested=C&trademark=E921775.
  33. ^ "EU QR Code Trademark". Archived from the original on 2012-09-15. http://archive.is/20120915/http://esearch.oami.europa.eu/copla/trademark/data/000921775.
  34. ^ "US QR Code Trademark". Archived from the original on 2012-09-15. http://archive.is/20120915/http://tess2.uspto.gov/bin/showfield?f=doc&state=4010:nrb6eh.2.6.
  35. ^ Information technology — Automatic identification and data capture techniques — QR Code 2005 bar code symbology specification, ISO/IEC 18004:2006 cor. 2009, pages 3, 6.
  36. ^ a b "Jargon Watch", Wired 20 (1): 22, January 2012.
  37. ^ "Malicious Images: What's a QR Code". SANS Technology Institute. 3 August 2011. Archived from the original on 2012-07-13. http://archive.is/20120713/http://isc.sans.edu/diary.html?storyid=11305. Retrieved 31 August 2011.
  38. ^ "Barcode Scanner". Google. 1 June 2011. Archived from the original on 2012-09-15. http://archive.is/20120915/https://market.android.com/details?id=com.google.zxing.client.android. Retrieved 31 August 2011.
  39. ^ "QR Droid". Google. 19 August 2011. Archived from the original on 2012-09-15. http://archive.is/20120915/https://market.android.com/details?id=la.droid.qr. Retrieved 31 August 2011.
  40. ^ "ScanLife Barcode Reader". Google. 24 May 2011. Archived from the original on 2012-09-15. http://archive.is/20120915/https://market.android.com/details?id=com.ScanLife. Retrieved 31 August 2011.
  41. ^ "Consumer Alert: QR Code Safety". Better Business Bureau. 23 June 2011. Archived from the original on 2012-07-15. http://archive.is/20120715/http://sandiego.bbb.org/article/consumer-alert-qr-code-safety-28037. Retrieved 31 August 2011.
  42. ^ "AVG Cautions: Beware of Malicious QR Codes". PC World. 28 June 2011. Archived from the original on 2012-09-07. http://archive.is/20120907/http://www.pcworld.idg.com.au/mediareleases/12655/avg-aunz-cautions-beware-of-malicious-qr-codes/. Retrieved 31 August 2011.
  43. ^ "EvilQR – When QRCode goes bad". AppSec-Labs Blog. 14 August 2011. Archived from the original on 2012-09-15. http://archive.is/20120915/https://appsec-labs.com/blog/tag/qrcode. Retrieved 31 August 2011.
  44. ^ "QR Codes: A Recipe for a Mobile Malware Tsunami". Cyveillance, Inc. 20 October 2010. Archived from the original on 2012-07-28. http://archive.is/20120728/http://www.cyveillanceblog.com/malware/qr-codes-a-recipe-for-a-mobile-malware-tsunami. Retrieved 31 August 2011.
  45. ^ QR Codes hold up to 2.9 KB whereas the smallest known computer virus is about one-tenth that size "The Smallest Virus I Could Manage". Virus Labs and Distribution. 1995. Archived from the original on 2012-09-15. http://archive.is/20120915/http://www.wiw.org/~meta/vlad.php?read=ARTICLE.5_2&issue=3&desc=Small%20Virus. Retrieved 31 August 2011.
  46. ^ "Beware of Malicious QR Codes". ABC. 8 June 2011. Archived from the original on 2012-08-01. http://archive.is/20120801/http://www.abc.net.au/technology/articles/2011/06/08/3238443.htm. Retrieved 31 August 2011.

[edit] Bibliography

[edit] External links

Wikimedia Commons has media related to: Quick Response Codes
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