> ## Documentation Index
> Fetch the complete documentation index at: https://docs.useanima.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# Mastercard VI

> Validate Mastercard Verifiable Intelligence credential chains using SD-JWT, ES256 signatures, and constraint-aware delegation rules.

# Mastercard VI

Mastercard VI uses SD-JWT credential chains to delegate payment authority from issuers to agents with explicit time and policy constraints.

## Layered Credentials

## Strong Signatures

## Credential Chain Model

* L1
* L2 Immediate
* L2 Autonomous
* L3a/L3b

## Algorithm Requirements

* JWS: ES256
* Curve: P-256
* Hash: SHA-256

## Constraint Types

| Constraint        | Intent                                                     |
| ----------------- | ---------------------------------------------------------- |
| allowed\_merchant | Permit transactions only for specific merchant identities. |
| line\_items       | Constrain purchasable SKUs/items and quantities.           |
| allowed\_payee    | Restrict destination beneficiary/payee account.            |
| amount            | Set max/min transaction amount boundaries.                 |
| budget            | Enforce cumulative spending ceiling over period.           |
| recurrence        | Define schedule rules for recurring charges.               |
| agent\_recurrence | Limit autonomous repeated actions by agent identity.       |
| reference         | Require transaction metadata/reference matching policy.    |

## Credential Chain Validation Example

```ts title="mastercard-vi-validate.ts" theme={null}
const result = await verifyViChain({
  algorithm: "ES256",
  credentials: {
    l1,
    l2,
    l3,
  },
  now: Date.now(),
});

if (!result.signaturesValid) throw new Error("Invalid signature chain");
if (!result.hashLinksValid) throw new Error("sd_hash mismatch");
if (!result.timeWindowsValid)
  throw new Error("Credential expired or not yet valid");

const policyDecision = evaluateConstraints({
  constraints: result.constraints,
  paymentRequest,
});

if (!policyDecision.allowed) {
  throw new Error("Constraint violation:" + policyDecision.reason);
}
```

> **Warning:** Never skip L3 terminal validation even when L1/L2 are valid. L3 binds the delegated chain to the immediate transaction context.

> **Tip:** Cache verified L1 trust anchors, but always recompute L2/L3 validity and constraint checks per authorization request.

> **Note:** Feed normalized constraint results into your shared decision engine to keep Mastercard VI aligned with Visa TAP and AP2 policy outputs.