Tangled Pin
During PIN generation, the system generates the following two extra values: the tangled PIN (a random set of numbers) and the key (used for obtaining a clear value for the PIN).
The tangled PIN has a predefined count of digits, which is a user-defined parameter (e.g. 20 digits), and is transmitted in the card welcoming letter. Later the cardholder receives the key via text message, which can be used to “untangle” (activate) the final PIN.