What is Flash SMS?
A Flash SMS is a message that appears immediately on the recipient’s mobile screen, without them having to open their message inbox, and then disappears for good once they dismiss it.
Flash SMS is available as a value-added service from some SMS providers, and is commonly used for messages that need to immediately catch the recipients’ attention.
Emergency alerts like flood or severe weather warnings are probably the best use case, although it is also used to send access codes as part of some authentication solutions (although not Infobip’s mobile authentication solution due to the security concerns outlined below).
The recipient does not need to open the mobile phone inbox to read the message and the message is not actually stored in the SMS inbox or even the phone’s memory. Once it has been dismissed by the recipient it is gone forever and is not available to anyone who gains access to the device.
Why is Flash SMS not secure?
When first created, the idea was to use Flash SMS to send confidential information like PIN codes and passwords, but practically it is not very secure as the Flash SMS will display on the mobile screen even when the phone is locked, along with a vibration and audible alert if one is set.
If the phone is on a table for example, then anyone nearby may see the message. That is a good thing if it is warning you of a tornado heading your way, but not so good if it is your credit card’s new pin code.