After four years of negotiation, in 2017 Google began paying Mastercard millions of dollars for access to the latter's piles of transaction data as part of its "Stores Sales Measurement" service. Google, which claimed to have access to 70% of US credit and debit cards through partners, said that double-blind encryption prevents both partners from seeing the other's users' personally identifiable information. Mastercard said the company shares transaction trends with merchants and their serviceā¦