IMEI, your phone, and you
It’s probably safe to say that everyone reading this article either has a cell phone currently, or has had a cellular telephone at some time in the past. Many of you may be familiar with what an IMEI is. It’s probably fair to say that even those who do know what an IMEI is, may not know what these little strings of numbers are actually used for.
IMEI versus MEID
IMEI stands for “International Mobile Station Equipment Identity” and is usually a 15-digit string of numbers which is considered to be “unique” (though there are limited cases where IMEIs may be re-used or even cloned). IMEIs are used to identify 3GPP (GSM, UMTS, and LTE) and iDEN phones. Some satellite phones use IMEIs for identification as well. CDMA providers, such as Sprint and Verizon, use a similar identifier called and MEID number, though some modern CDMA phones have both an MEID and IMEI.
Think of your IMEI as a serial number for your cell phone. It’s usually printed on a sticker inside the battery compartment of your phone, and can usually be found somewhere on the box you bought it in. It’s also programmed into the phone itself, that’s the most important place that you’ll find it.
In GSM and LTE networks, the IMEI is used to identify devices and can be used for stopping a phone that has been reported stolen from being able to access a carrier’s network. For this to work the carrier must have access to the “stolen phones” database and has to participate in blocking phones that have been reported stolen.
IMSI and your SIM card
Since the IMEI is supposed to be unique, many may jump to the conclusion that it can uniquely identify a person. Although some may make a valid argument for that correlation, the IMEI is only supposed to be used for identifying the device, and should not have a permanent (or even semi-permanent) relation to the individual subscriber. Subscribers are identified with IMSI numbers which are typically stored on a Subscriber Identity Module — your SIM card. This SIM, in theory, can be removed from your phone and placed in another for almost immediate access to your provider’s network from the new device. Unfortunately, many carriers still lock their devices so they can only be used by their subscribers while on their networks.
Depending on your OS, apps may have access to your IMEI. iOS just did away with this permission while Android still lets apps use it — as long as they declare they’re accessing your personal information when you install such an app.
Some developers use the IMEI to keep track of you and your device for such things as anti-piracy measures and app verification. It sounds creepier than it is, and developers are advised not to use your phone’s IMEI in this fashion. There are much easier ways for developers to save settings and restrict access than through the use of your IMEI.
Sooner or later IMEIs are going to give way to the next iteration: IMEISV. This new number will essentially take the place of the “obsolete” IMEI, and replace it with a new type of number. This new format will be used the same way as the old IMEI, but its data structure will be different.
Like your IMEI of today, you probably will never need to know your IMEISV, but at least now you know what all those strange “identification” acronyms are and what they’re used for.
Image Credit: (CC) Mooby