Validity of a QR Code

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7

I have a QR Code that leads to a link. This link, I suppose, will be on the air until 2015. Of course, when the link doesn’t exist, this QR Code will get you nowhere.

My question is: Does this code have validity? Or, for example, someone in Transylvania can generate a QR Code identical to mine.

I ask this because I intend to store them.

qrcode

3 answers

11


I have a QR Code that leads to a link. This link, I suppose, will be on the air until 2015. Of course, when the link doesn’t exist, this QR Code will get you nowhere.

  • That’s basically it. It will probably go to a 404 or to a server not found.

My question is: This code is valid?

  • The code will be read at any time, because the information contained in it does not depend on anything external.

Someone in Transylvania can generate a QR Code identical to mine?

  • Absolutely. The content of QR Code is just a stream of bytes, which output a string. Just use the same string, and here is the QR with identical value. And the coolest, not even need to be in Transylvania for this.

    Even if the person uses the same compression and encoding criteria, the image will be identical.

I ask this because I intend to store them.

  • Do you want to store the image or link? (remember that it’s not just links that can be stored,in a QR Code. Any string can be stored, with the most diverse purposes)

    The most common purposes are links, wi-fi connection data and electronic business cards. But there are still internal usage codes, like packaging identification, or anything else you can imagine replacing conventional bar codes.

    If you are storing the images, you will probably be storing more information than necessary, unless you had a very special use for the encoding features used (which is unlikely).

Suggestion for those who create their own codes:

Do not use short third-party links. Create your short link system, and store the data in your own DB, preferably under an internet domain that you can maintain for as long as you like.

See the main reasons:

  • You prevent the "expire" link, or cease to exist if the short link provider has problems or time.

  • You can fix a wrong link. I’ve seen a case where a large-scale magazine had to come to an agreement with a famous link shortener, thanks to a link that was misposted on the cover of the magazine. If you manage your own links, just replace the wrong one with the correct one in DB, and the problem is solved.

  • You can point a QR from an old link to a friendly message warning that the link has expired, instead of simply breaking access, creating a better user experience, and perhaps directing you to something else interesting, not missing the visit.

Note: I say short links, because the less information, the better the readability of a QR Code. Remember that when it is the case, you can practically use 7KB in a single code, but in practice, only with a professional scanner you will be sure to read a QR with so much information.

In fact, I humbly venture to say that the people who standardized the receipt of NFC-e - which began to be used in some states in place of the fiscal coupon - made a big mistake by putting a lot of unnecessary information in the QR Code, making the same "priceless" by many devices. And look that one of the premises was that of the trader save on the printer used. In practice, the printer has to be good, and the reader too. If they had done it more wisely, even a dot matrix printer would solve.

6

Most solutions of this kind[Citation needed] involve the definition of expiration in the database, the code being present in QR Code only one ID pointing to the record.

The expiration encoding directly in the code can use a value that expresses a Timestamp defining the period or date of validity.

You will need a maximum of 8 bytes to store one Timestamp defined in accordance with ISO 8601.

According to Wikipedia entry, a QR Code can contain up to 7089 bytes (or approx. 6.9 kb).

3

I believe it has no validity, because QR Code is a standard, as is the barcode. When a QR Code reader is used to read your code, it will simply translate the code into the link you used to create it.

I took the test myself, I found a magazine from a couple of years ago with a code and he read it normally, just the link that was in it no longer existed.

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