Creating QR code for wireless networks

A quick solution to bring a mobile phone into a wireless network is via QR Code.

On the internet there are a lots of QR code generator web sites available, but my problem with those is that I do not know what happens with the data I enter.

By looking for a “secure” solution I came across qrencode, which is running on Linux.

qrencode can be easily installed on a Debian Linux system by using the command below:

  #apt install qrencode
String for WiFi SSID

WiFi SSID

For a WiFi SSID, qrencode expects a string in a specific format, which looks like this:

  WIFI:S:Apple-Sucks;T:WPA;P:secret1234;H:true;;
String for WiFi SSID
  • S = Wireless SSID

  • T = Encryption

  • P = Password

  • H = true if SSID is hidden

To generate the QR code I’m using this command, which writes the output in a PNG image (-o). As error correction level I’m using high, which allows 30% destruction of the QR code (-l H).

  $qrencode -o wifi.png -l H "WIFI:S:Apple-Sucks;T:WPA;P:secret1234;H:true;;"
qrencode with WiFi string
QR code test with WiFi string
QR code test with WiFi string

MeCard

It’s also possible to share contact details via QR code, in this case the format is MeCard. The string in this case can look like this:

  MECARD:N:Stefan Thierolf;ORG:thierof.org;TEL:+49 123 456 789;URL:https\://thierolf.org;EMAIL:hello@thierolf.org;ADR:Musterstrasse 1, 12345 Musterstadt, Germany;;
String for WiFi SSID
  • N = Name

  • ORG = Organization

  • TEL = Phone Numbers

  • URL = Web sites

  • EMAIL = Email address

  • ADR = Street address, postal code

The command to write a MeCard would look like this.

  $qrencode -o mecard.png -l H "MECARD:N:Stefan Thierolf;ORG:thierof.org;TEL:+49 123 456 789;URL:https\://thierolf.org;EMAIL:hello@thierolf.org;ADR:Musterstrasse 1, 12345 Musterstadt, Germany;;"
qrencode with MeCard string
QR code test with MeCard string
QR code test with MeCard string

QR code scanner

To scan QR codes on my mobile phone, I’m using the Privacy Friendly QR-Scanner App from KIT (Karlsruher Institut für Technologie) because I personally value privacy and data protection. This app does not have any advertisements or shares data with doubtful companies like facebook (via a dubious API for example).


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