The Electronic Serial Number (ESN) is a unique 32-bit identifier recorded on a secure chip in a mobile device by the manufacturer.

The Electronic Serial Number (ESN) is a unique 32-bit identifier recorded on a secure chip in a mobile device by the manufacturer.

• A. 16-bit identifier
• B. 24-bit identifier
• C. 32-bit identifier
• D. 64-bit identifier

Answer: (C)

The key idea is that the ESN is a fixed 32-bit value used to uniquely identify a mobile device on CDMA networks. This 32-bit length provides 2^32 possible values, or about 4.29 billion unique identifiers, which is sufficient to distinguish devices in widespread use and is the standard format chosen by manufacturers for ESNs. Smaller widths like 16- or 24-bit would create too few unique IDs and could lead to collisions, while a 64-bit length would be more than what the ESN specification requires and is not how ESNs are defined. In practice, the ESN is stored in a secure area of the device hardware to prevent tampering, making it a reliable identifier during forensic investigations.

The key idea is that the ESN is a fixed 32-bit value used to uniquely identify a mobile device on CDMA networks. This 32-bit length provides 2^32 possible values, or about 4.29 billion unique identifiers, which is sufficient to distinguish devices in widespread use and is the standard format chosen by manufacturers for ESNs. Smaller widths like 16- or 24-bit would create too few unique IDs and could lead to collisions, while a 64-bit length would be more than what the ESN specification requires and is not how ESNs are defined. In practice, the ESN is stored in a secure area of the device hardware to prevent tampering, making it a reliable identifier during forensic investigations.