Reviewed by Sep 30, 2020| Updated on
A credit card authorisation key is a numeric series that is to be entered during a credit card transaction to confirm that the cardholder has enough funds to make a purchase. It is also known as credit card authorisation code.
When a credit card is swiped, the details of the credit card are encrypted at the point-of-sale (POS) terminal. It is sent to the payment gateway provider in order to route the request to the credit card issuer.
When the card-issuing company receives the encrypted request, it verifies if the account has sufficient funds. If sufficient funds are available, the credit card company will send a credit card authorisation key to the merchant at operating POS terminal.
The authorisation keys are normally six-digit long, typically being a combination of credit card and transaction information, i.e. transaction amount and time stamp. It acts as a reference to a particular entry if the transaction must be voided or reversed.