剣道 Kendo Cards — Physical Proof of Identity

One-Line Pitch

A physical NFC card — styled like a collector’s item, anchored to a cryptographic proof chain — that proves you’re real, ships to your door, and cannot be faked.

The Spark

Everything digital is easy to fake. Screenshots, profile photos, links — none of it proves anything. A physical card you can hand to someone, that they can tap with their phone and watch it verify against a live proof chain, is a different category of object entirely. That’s an Oyster card for identity: a physical artefact you carry that does something when touched.

The Evolis Primacy 2 in the studio prints full-colour CR80 PVC — the same size and feel as a credit card or an Oyster card. We can put anything on it, program any NFC chip in it, and embed a cryptographic anchor that links back to a KendoSoil node. The result is a card that is provably real, provably unique, and provably yours.

Products

Product	Price	Qty	What You Get
NFC Business Card Pack	£99	10	Custom-designed full-colour PVC cards, NFC-programmed with your identity anchor
Collector Card	£25	1	Limited-run numbered art card — NFC proved, signed, unique
Creator Pack	£349	50	Full custom kit — design consultation, NFC programming, full proof chain setup

How It Works

The Card

Printer: Evolis Primacy 2 — YMCKO ribbon, full-colour on CR80 0.76mm PVC
Format: Standard credit card size. Lamination optional.
NFC chips: MIFARE DESFire EV2 / NTAG 424 DNA — secure, read-protected if needed

The Proof Chain

At print time: A SHA-256 hash of the card’s identity data is computed
Anchored: The hash is submitted to the Kronos Architecture and logged on a KendoSoil node
Signed: The anchor is signed with Ed25519 — your card gets a proof receipt
Stored on chip: The card’s NFC chip stores the anchor ID

Verification

Someone taps your card with any NFC-capable phone → their browser opens https://verify.kendocards.com/?uid=XYZ → live lookup against the proof chain → ✓ or ✗ in under a second.

No app required. No account. Just tap.

The Stack

kendocards.com (Next.js)
├── /products         → product listings + checkout
├── /proof            → public verification page (tap-to-verify)
├── /receipt          → order confirmation + proof anchor display
└── /api/checkout     → FortKnox payment flow
        ↓
FortKnox (payment processing)    ← see <a href="https://count.krisadamstv.com/link-click?from=kendo-cards&to=fort-knox" class="idea-link" target="_blank" rel="noopener">Fort Knox idea<span class="idea-link-arrow">&#8599;</span></a>
        ↓
Proof Server (proof anchoring)   → proof.krisadamstv.com
        ↓
KendoSoil (node storage)         → kendo.kitzuna.com (Amsterdam)
        ↓
Evolis Primacy 2 (physical print + NFC programming)

The Physical Production Flow

Order placed on kendocards.com
    ↓
FortKnox debit confirmed
    ↓
Design file generated (SVG → Evolis-ready BMP)
    ↓
Proof anchor computed + submitted
    ↓
Card printed on Evolis Primacy 2
    ↓
NFC chip programmed with anchor ID
    ↓
Card quality-checked + photographed
    ↓
Shipped (Royal Mail or DHL)

Live Verification — What the User Sees

When someone taps a Kendo Card NFCchip:

https://verify.kendocards.com/?uid=KD-2026-001-a4f7e2

Card UID:     KD-2026-001-a4f7e2
Issued to:    Kris Adams
Issued:       2026-02-14
Proof anchor: sha256:a4f7e2...
KendoSoil:    kendo.kitzuna.com  ✓ confirmed
Signed:       Ed25519 ✓

A card that fails any of these checks shows a red ✗. You cannot fake a valid verification — the anchor is on the node, not on the card.

Why Physical?

Digital identity is abundantly faked. A physical object with verified provenance is the opposite signal. “Here is a card you can hold, tap, and verify — it cannot be reprinted from a screenshot.”

This is the same instinct as a wax seal, a stamped passport, a holographic sticker — except the verification is cryptographic and the source of truth is a distributed node, not someone’s opinion.

Payments: Fort Knox Integration

Checkout on kendocards.com triggers a Fort Knox↗ debit flow. Fort Knox handles: - Stripe payment capture - Internal credit allocation (PGLB) on repeat orders - Webhook to trigger print queue

This means no payment logic lives in the Kendo Cards codebase — we consume the Fort Knox API and that’s it.

Constraints & Reality Check

Production throughput: The Primacy 2 prints ~140 cards/hour. Fine for current volumes, needs a second unit or outsourcing at scale.
NFC programming time: ~10 seconds per card for MIFARE DESFire EV2 key derivation. Not a bottleneck at current volumes.
Proof anchor latency: KendoSoil confirmation is typically <2 seconds. Batching anchor submissions would speed this up at scale.
Shipping: Royal Mail First Class is fine. DHL for international. Tracked as standard on Creator Packs and above.
Card design: SVG-first workflow. We have templates. Custom designs need a 48h turnaround before print.
GDPR / Identity data: We anchor a hash, not the data itself. The underlying data stays in Supabase under the user’s account. Deletion works.

Next Actions

Build the /filename API endpoint that compiles card designs to Evolis-ready print files
Automate the proof anchor submission on order confirmation
Set up NFC programming station next to the printer
Design the verification page at verify.kendocards.com
Add PGLB discount on repeat orders via Fort Knox credit system