IMEI vs. IMSI

It is common for most of us to not pay attention to details like IMEI and IMSI numbers. In the event that we have to use them, we are not even aware of what they are or where to find them when we need them. How can we even compare them or do we even have to know what they have in common? What are the differences between them? In terms of privacy and security, these are critical questions you should ask. The following post will answer some of the questions you may have before it's too late and you have lost all your chances.

Surely most of us have heard of the IMEI number and its use in case our device is lost or stolen. The IMEI number is unique and finding it is easy. However, do you know what an IMSI number is? and what its use is? If not, then today you will learn more and find out the difference between an IMEI and IMSI number.

Recommended: What is the difference between IMEI vs. MEID?

What is IMEI?

The IMEI acronym stands for International Mobile Equipment Identity, which is a unique identifier for mobile devices. A unique number is assigned to each mobile phone so that it can be uniquely identified. It is a 15-digit number that can be found on the back of almost every device that has a SIM card slot and a SIM card slot. It is common for smartphones to have their IMEI numbers engraved on the battery compartment of the device. In spite of the fact that most smartphones are difficult to open, you can ask for your smartphone's IMEI number by dialing *#06#. Based on the Luhn algorithm, the last number in the equation is calculated.

It is critical to note that IMEI is not a SIM card number, but an identifier for the device. As a result, changing the SIM card does not have any impact on the device. In the event that your device is lost or stolen, the IMEI number can be used to block your device. This will ensure that it is protected from the malicious activity if the device is lost or stolen.

In addition to other information about the phone's model, origin, and serial number, IMEI numbers also contain information about its manufacturer. It is also worth mentioning that most manufacturers print the IMEI number on the box in which the smartphone is packaged. From the phone box, you may be able to get the IMEI number of your phone if you have lost access to it.

The Structure of an IMEI Number

IMEI numbers either come in a 17-digit or 15-digit sequence of numbers. The IMEI format currently utilized is AA-BBBBBB-CCCCCC-D:

AA: These two digits are for the Reporting Body Identifier, indicating the GSMA-approved group that allocated the TAC (Type Allocation Code).
BBBBBB: The remainder of the TAC (FAC)
CCCCCC: Serial sequence of the Model (SNR)
D: Luhn checks the digit of the entire model or 0 (This is an algorithm that validates the ID number) (CD)

What is IMSI?

IMSI refers to the International Mobile Subscriber Identity, often abbreviated as IMSI. The number has a length of 15 digits as well. It is possible, however, that there may only be 14 digits in some cases. It is a unique number stored in a 64-bit field on the SIM card that identifies a phone network customer.

As you know, the MCC (Mobile Country Code) is represented by the first three numbers of the IMSI code. An MNC (Mobile Network Code) is the number that comes after the MCC and is two digits in length according to European standards and three digits in accordance with North American standards. MSIN (Mobile Subscription Identification Number) is the series of ten digits that make up the rest of the code.

A combination of the MCC and MNC is also created in order to create the HNI (Home Network Identity). In order to identify a subscriber's home network, HNIC can be used. In order to identify the specific mobile number that belongs to the network that is being used by HLC (Home Location Register), an IMSI number needs to be assigned.

The structure of IMSI

This is how IMSI is grouped:

The first three digits represent the mobile country code
The second two are known as mobile network codes
There are no labels on the remaining ten digits

Here is an example: 252 90 1234747411

IMEI & IMSI: When to use them?

It is crucial to keep in mind that, since IMEI numbers are unique and cannot be changed easily, they are the most useful in tracking and recovering lost or stolen phones. There is a global registry that contains all IMEI numbers like EIR (Equipment Identification Register) that can be used to identify the mobile phone and therefore identify the owner of the phone. In order to blacklist or block your phone, you will need to contact your telecom provider. Blacklisting a phone means it will never work on any network, which means that all SIM cards will never work on that phone. As a result, the phone is pretty much useless at this point. As far as Wi-Fi is concerned, I think it should still work.

Using aftermarket tools, hackers are able to change the IMEI number of the phone to make a quick profit. As a result of this, you can unblock your device, which in many countries is considered to be a criminal offense. Hackers are able to carry out their attacks a great deal easier if they possess tools capable of assigning a fictitious IMEI number to a phone (also known as spoofing) so that it can be unlocked and used with a different SIM card again once it has been unblocked. In the case of a spoof IMEI number that is misused for nefarious purposes, you may face legal consequences.

Alternatively, if you transfer your SIM card from one phone to another, the IMSI number from the previous phone will be carried across to the replacement phone that has been inserted with the SIM. Since the IMEI number is tied to the phone, it stays with it. It is the IMSI number that is used by telecom operators to identify the customer as well as to identify all the services that he/she has subscribed to. There are many services provided by the company, including your calling, messaging, internet, and other services that are available to you.

Concerns about security

It's important to keep your IMEI and IMSI safe from nefarious apps and trackers. You can be tracked and located by hackers using your IMEI number. They can even use them to access your financial accounts after they have stolen your information.

Furthermore, if a phone does not have an IMEI number, it is either a counterfeit or an invalid phone. Irrespective of how attractive the price is, you shouldn't buy it. What is the most reliable way to verify the validity of your IMEI number? In that case, you can match what's on the software interface with what's printed on the product's back and packaging. Another method of checking it is to use the LUHN formula.

In the same way, hackers can intercept calls, messages, and mobile data through IMSI numbers. This is due to the fact that the SIM card's IMSI number is directly tied to the subscriber's account and is used to provide relevant services. Data associated with IMSI numbers can be captured by spoofed access points and relayed to the nearest cell tower. It is common for Hollywood movies to show that trick of tracing calls and all that. The actual implementation of such a technique, however, is extremely complex. Nevertheless, it's not impossible.

In addition to being tied to the SIM and responsible for communication between the SIM and the cell tower, the IMSI number can also be used to track the movements of the user since it is associated with the SIM. In that case, the location of the cell towers is used to triangulate the position of your phone.

Having said that, mobile apps can extract the IMEI and IMSI of your device. This allows them to create a profile of your usage patterns that can be used to identify you personally. There are several companies that can show you ads that are specifically tailored to your interests based on your browsing activities, for instance. The question arises then, how was it that that company knew you wanted to buy a brand-new jacket, and how did they know that? There is a possibility that it could be any app on your phone that you have blindly allowed to access any information that is on it. Is there any other reason why you would suspect that your phone is spying on you? So, that's how you get "personalized targeted" ads based on your “personally identifiable profile” data.

How to find the identity of your phone?

IMEI is a unique identifier for the phone that is attached to it and is used to identify the phone. An IMSI is a unique number that is attached to a SIM card and is used to identify the subscriber and the services assigned to him/her. As the SIM card moves from phone to phone, the IMSI remains with the phone, but the IMEI remains with the handset. The IMEI number will be helpful for you as an end user in preventing lost or stolen mobile devices from being accessed by others.

Basically, that's what it boils down to. It is always a smart idea to keep your IMEI number somewhere safe so that when the time comes, you will know where it is. Simply take a screenshot and save the image to your cloud account if you can see the IMEI number in the Settings' About section of the app.