If returned, this value will be used in the creation of certain Authentication Values (AV) for EMV 3DS. The value passed must conform to the current AV value the issuer is using. This may also depend on the card brand of the transaction. For example, CAVV and IAV accept different values.
On Challenge responses (Stepup, Initiate, Validate) this value is currently ignored for CAVV usages in favor of mapping to the “Credential Type”. For Enhanced IAV SPA2 usage, if passed, this value will override the mapping to the “Credential Type”.
Note: This value will be converted to the Hexadecimal equivalent. Please see the “VCAS Enhanced Authentication Value Support Guide” for more details on current AVs available and the corresponding values.