Luhn algorithm
The Luhn algorithm is a mathematical checksum formula used to calculate the 15th check digit of an IMEI number to instantly detect accidental transposition or typing errors.
When a device attempts to connect to a network, the baseband logic uses this mathematical formula locally. If a user mistypes the 14-digit sequence, the resulting math will not align with the 15th digit, and the system will reject the string instantly before pinging external databases, saving valuable processing power.
