DEFINITION of 'Interbank National Authorization System (INAS)'
A network of banks that are affiliated with Mastercard International. The network facilitates the worldwide exchange of bankcard authorizations between different financial institutions. The network is used for both credit and debit cards bearing the Mastercard logo.
BREAKING DOWN 'Interbank National Authorization System (INAS)'
INAS is related to the Mastercard system INET, which have been combined into Banknet, a worldwide data communications network. Together, these two systems facilitate all Mastercard transactions everywhere.