ESN: Electronic Serial Number

An Electronic Serial Number is used for the identification of mobile devices. The primary purpose of this is to verify if a user is legitimate.

The 32 bit long ESN includes 8 bits representing the manufacturer code, an 18-bit serial number which is unique, and 6 bits reserved for future applications.

Applications of the ESN

The ESN is used where there is a need for uniqueness in identification. Some of the applications are listed below:

• The ESN is particularly useful for identifying stolen cellular phones, even if the SIM card is changed. Apart from this, it can be used to prove that a certain mobile device was used to make or receive a call. Other key uses include tracking for inventory and warranty claims.
• The ESN in mobile devices can be used for time attendance and registration tracking as well.