Protocol Version 2.0 IETF RFC 9162 & RFC 8785 Hardware Attested (AMD SEV & Intel TDX)

Ashlar Blue Institutional & Developer Documentation

The non-custodial institutional D-FMI platform enabling trading desks and autonomous settlement engines to discover clearing endpoints via DNS, verify counterparty execution inside hardware enclaves, and execute deterministic multi-rail DvP/PvP settlement.

# Platform Overview

Ashlar Blue addresses the fundamental constraint of institutional cross-rail clearing: transaction graph surveillance and counterparty settlement risk. When institutions transact across public and permissioned ledgers without enclave isolation, their bilateral books, margin positions, and execution strategies are exposed to external observation.

Ashlar Blue unifies three core technologies into a single non-custodial clearing layer:

  • Hardware Enclaves (AMD SEV-SNP & Intel TDX): Continuous 24/7/365 post-match multilateral netting, SPAN 2 / ISDA SIMM cross-margining, and signature validation execute within hardware-isolated memory perimeters inaccessible to hosts, cloud providers, or operators.
  • Dual-Stack x402 Clearinghouse Authority: Gasless two-phase DvP/PvP settlement routing using canonical EIP-3009 authorizations, ISDA CDM bindings, and IETF DNS discovery.
  • IETF SCITT Transparency Receipts (RFC 9162): Every settlement emits a 384-byte merkleized Digital Regulatory Reporting (DRR) receipt verifiable offline in sub-millisecond latency without calling live APIs.
🛡️ Non-Custodial D-FMI Architecture & Locked-Down Production Gate

Neither Ashlar Blue nor the clearinghouse ever takes custody of funds. Counterparties sign standardized authorizations (such as EIP-3009 receiveWithAuthorization or ISDA CDM mandates). The non-custodial clearing relayer broadcasts the settlement, and funds transfer directly between counterparties atomically. Live production settlement requires Stage 01–04 Bilateral Admission (onboarding.html).

# 5-Minute Quickstart

To interact with an x402 clearing endpoint on Ashlar Blue, follow the two-step handshake:

Step 1: Probe the Resource for the 402 Challenge

Send an unauthenticated request to the clearing endpoint. The server responds with HTTP 402 Payment Required containing the accepted settlement rails and terms in the canonical payment-required header:

curl -i -X POST https://api.ashlar.blue/settle/isda

Step 2: Interactive Live Endpoint Probe

Test the live D-FMI settlement endpoint directly from this documentation portal:

🧪 Live x402 Endpoint Probe Production API
// Click "PROBE" to execute a live x402 challenge request against production infrastructure...

# The x402 Protocol Wire Specification

Ashlar Blue operates a dual-stack x402 v1 / v2 non-custodial clearing authority. In x402 v2, settlement requirements are delivered in the payment-required Base64 response header:

HTTP 402 Response Headers
HTTP/2 402 Payment Required
Content-Type: application/json; charset=utf-8
Access-Control-Expose-Headers: payment-required
payment-required: 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

Decoded, the challenge contains an array of acceptable offers identified by CAIP-2 network identifiers:

Field Type Description
x402Version number Protocol major version (2 for v2 emission).
resource.url string Fully qualified URI of the resource being accessed.
accepts[].scheme string Settlement scheme (e.g. "exact").
accepts[].network string CAIP-2 network identifier for supported multi-rail settlement adapters.
accepts[].amount string Atomic token units required (e.g. "100000" = 0.10 settled units, 6 decimals).
accepts[].payTo string Recipient address designated to receive funds upon settlement.

# DNS Discovery Specification (_x402)

Institutional OMS/EMS systems and settlement engines discover clearing endpoints without centralized registries by querying standard DNS TXT records defined under the IETF x402 DNS Discovery draft.

To announce an x402 settlement authority for a domain, configure the _x402 apex record:

DNS TXT Record Format
_x402.ashlar.blue. IN TXT "v=x402-1; wk=https://api.ashlar.blue/.well-known/x402; k=facilitator; net=multi-rail; scheme=exact"

# Hardware Enclave Silicon & Remote Attestation

All clearing decisions and cryptographic verifications on Ashlar Blue execute inside attested hardware execution environments: AMD SEV-SNP and Intel TDX.

Enclave Architecture Silicon Generation Attestation Provider Verification Method
AMD SEV-SNP AMD EPYC™ Milan / Genoa Google Cloud Confidential Space OIDC JWT token signed by confidentialcomputing.googleapis.com
Intel TDX v4 4th/5th Gen Intel Xeon Scalable Intel SGX / TDX DCAP ECDSA P-256 quote hash verified against hardware build measurement digests

Verifying Remote Attestation

Integrators can independently verify the enclave's code integrity using the verify_tdx_quote or get_enclave_attestation tool over the Model Context Protocol (MCP) or via our public API endpoint.

# Model Context Protocol (MCP) Server

Ashlar Blue provides a full-featured MCP server (@ashlar-blue/x402-trust v0.5.95) enabling institutional engineering teams and automated compliance agents to discover clearing endpoints, verify enclave attestation, and validate SCITT receipts.

MCP Client Configuration
{
  "mcpServers": {
    "ashlar-trust": {
      "command": "npx",
      "args": ["-y", "@ashlar-blue/x402-trust", "mcp"]
    }
  }
}

Core Tool Reference

Tool Name Parameters Purpose
discover_x402_endpoint domain Resolves DNS TXT records to discover clearinghouse settlement endpoints.
verify_tdx_quote quoteHex, expectedMrtd Validates Intel TDX hardware attestation quote against reference hashes.
canonicalize_jcs_payload payload Normalizes JSON data strictly according to RFC 8785 (JCS).
submit_gasless_settlement authorization, requirement Dispatches an EIP-3009 payment authorization to the clearing engine.
reconcile settlementTx, payee Confirms on-chain settlement verdict and produces audit proof.

# REST API Reference

The non-custodial clearinghouse exposes clean HTTP endpoints for pre-settlement verification, atomic DvP/PvP settlement, and capability discovery.

POST /verify

Pre-verifies an EIP-3009 authorization before broadcast to confirm signature validity, nonce status, and sufficient balance.

cURL Example
curl -X POST https://api.ashlar.blue/verify \
  -H "Content-Type: application/json" \
  -d '{
    "x402Version": 2,
    "paymentPayload": {
      "from": "0x118970D2b9c36fB65Eb00F0203Ad5DF...",
      "to": "0x3c36450b84b7b9712A396ab4e1b551888ab36599",
      "value": "100000",
      "validAfter": 0,
      "validBefore": 1788700000,
      "nonce": "0x8f2d...",
      "v": 27,
      "r": "0x...",
      "s": "0x..."
    }
  }'

GET /supported

Returns the live array of supported multi-rail settlement adapters, tokens, and hardware enclave environments.

Response Payload
{
  "networks": [
    { "name": "multi-rail-direct", "caip2": "eip155:8453", "type": "evm" },
    { "name": "multi-rail-ledger", "caip2": "xrpl:0", "type": "settlement" },
    { "name": "multi-rail-attested", "caip2": "eip155:14", "type": "evm" },
    { "name": "multi-rail-enterprise", "caip2": "eip155:50", "type": "evm" }
  ],
  "enclaves": ["GCP_AMD_SEV_SNP", "INTEL_TDX_V4"],
  "standards": ["x402-v2", "EIP-3009", "RFC-8785", "IETF-SCITT-RFC-9162"]
}