What it is
The Kernel Identifier tells the reader which contactless kernel to activate for the selected application. At the entry point (EMV Book B) the reader reads the PPSE directory, and the Kernel Identifier — combined with the AID — resolves which Book C kernel (2–8) processes the tap.
This is the mechanism by which one contactless reader supports many schemes: the card effectively names its kernel, and the reader dispatches to the matching processing logic.
Where it appears
Read from the PPSE directory entry during application selection.
Specification reference
Defined in: EMVCo Contactless Book B (Entry Point Specification)
Example values
02Activate Kernel 2 (Mastercard)
03Activate Kernel 3 (Visa)
Meaning by contactless kernel
Kernel 2· Mastercard
Short kernel id 0x02 (or a long registered id) routes the tap to the C-2 kernel.
Kernel 3· Visa
Routes to the C-3 kernel; Visa AIDs default to Kernel 3 when no explicit id is present.
Kernel 7· UnionPay
Selects the C-7 (QuickPass) kernel.