A provision of U.S. regulation common to financial services regulation requiring that users must identify themselves. This regulation has led to geo-blocking of U.S. customers from certain decentralized exchange functionalities. 

KYC means Know Your Customer and sometimes Know Your Client. KYC or KYC check is the mandatory process of identifying and verifying the client’s identity when opening an account and periodically over time. In other words, banks must make sure that their clients are genuinely who they claim to be.