A fasce is a tariff model in which the price changes according to the time band or usage period. In energy billing, this usually means different rates for peak, off-peak, or other defined hours. The same concept appears in many digital services: a system stores a pricing rule, applies it based on timestamps or usage windows, and then calculates the bill from those rules.
In cyber security, time-band pricing matters because the tariff logic often lives in customer portals, APIs, and billing engines. Attackers may exploit weak validation to alter the selected tariff, tamper with usage times, or confuse users through phishing pages and fake invoices that misstate the rate structure. Defenders protect these systems by checking server-side pricing rules, logging tariff changes, and ensuring the interface, contract summary, and bill all match. Clear tariff handling reduces fraud and prevents disputes over what was actually authorized.