How EMVCo's contactless specification fans out into seven scheme kernels and the unified Kernel 8: the structural dependency tree, what happens during a tap, and how the scheme kernels converge into C-8.
Kernel-to-scheme mapping
Book B (Entry Point) reads the card's AID and activates exactly one Book C kernel. Each kernel below links to its full guide.
Kernel 1 (C-1) is retired — removed in Book A v2.7; its Visa AIDs migrated to C-3 and JCB AIDs to C-5.
Structural dependency
Spec families → Books → kernels → schemes, mapped onto the L1/L2/L3 runtime stack. Solid lines are static composition; the orange path is the Entry Point's runtime, AID-driven dispatch.
Runtime tap sequence
What happens during a tap: PPSE → candidate AID list → Entry Point match → kernel activation → outcome. Book B drives the dispatch; the activated Book C kernel then runs the exchange.
APDU detail is illustrative; exact tags and flow vary by kernel and Books A–D bundle version.
Convergence to Kernel 8
Six scheme kernels run in parallel under one Books A–D bundle, then fold into the unified EMVCo kernel. Verified anchors marked ◆: C-1's retirement and C-8's publication (v1.0 Oct 2022, v1.1 2022/23).
PayProbe note: C-2…C-7 stay live during rollout — test both the scheme kernels and C-8 in parallel.