HODLXXI Bitcoin Identity

Overview

Use this skill to integrate HODLXXI (Universal Bitcoin Identity Layer) for agent authentication, LNURL-Auth linking, and JWT-based identity claims.

Installation

1. Fetch the skill file from the repository (raw link works for installable agents):

curl -L -o SKILL.md \
  https://raw.githubusercontent.com/hodlxxi/Universal-Bitcoin-Identity-Layer/main/skills/public/hodlxxi-bitcoin-identity/SKILL.md

1. Install helper dependencies for local verification scripts:

python -m pip install ecdsa pyjwt requests

Quick start

1. Set a base URL for the HODLXXI deployment.
2. Register an OAuth client to obtain client_id and client_secret.
3. Run the OAuth2/OIDC authorization code flow (PKCE recommended).
4. Start an LNURL-Auth session for Lightning wallet login.
5. Verify JWTs with the JWKS endpoint.

Usage steps

1) Configure the base URL

Set the base URL to the HODLXXI deployment (update as needed):

BASE_URL="https://hodlxxi.com"

2) Register an OAuth client

Register a client to get credentials:

curl -X POST "$BASE_URL/oauth/register" \
  -H "Content-Type: application/json" \
  -d '{"client_name": "YourAgentName", "redirect_uris": ["https://your-callback-url"], "scopes": ["openid", "profile"]}'

Store client_id and client_secret securely.

3) Run OAuth2/OIDC authorization code flow

Discover endpoints:

curl "$BASE_URL/.well-known/openid-configuration"

Create an authorization request (PKCE recommended):

curl "$BASE_URL/oauth/authorize?client_id=your_client_id&redirect_uri=your_callback&response_type=code&scope=openid%20profile&code_challenge=your_challenge&code_challenge_method=S256"

Exchange the authorization code for tokens:

curl -X POST "$BASE_URL/oauth/token" \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "grant_type=authorization_code&code=received_code&redirect_uri=your_callback&client_id=your_client_id&code_verifier=your_verifier"

Expect an access token, ID token (JWT), and optional refresh token.

4) Start an LNURL-Auth session

Create a session and show the LNURL to the user:

curl -X POST "$BASE_URL/api/lnurl-auth/create" \
  -H "Accept: application/json"

Poll for completion after the user scans the LNURL with a Lightning wallet:

curl "$BASE_URL/api/lnurl-auth/check/your_session_id"

5) Verify JWTs

Fetch JWKS:

curl "$BASE_URL/oauth/jwks.json"

Verify with Python (example uses PyJWT):

import jwt
import requests

jwks = requests.get("https://your-hodlxxi-deployment.com/oauth/jwks.json", timeout=10).json()
public_key = jwt.algorithms.RSAAlgorithm.from_jwk(jwks["keys"][0])
claims = jwt.decode(your_jwt, public_key, algorithms=["RS256"], audience="your_audience")
print(claims)

6) Monitor health and metrics

Check liveness and OAuth system status endpoints:

curl "$BASE_URL/health"
curl "$BASE_URL/oauthx/status"

Code examples

Register a client from a JSON template

curl -X POST "$BASE_URL/oauth/register" \
  -H "Content-Type: application/json" \
  -d @templates/oauth-client.json

Create LNURL session and poll

session_json=$(curl -s -X POST "$BASE_URL/api/lnurl-auth/create")
session_id=$(python3 -c 'import json,sys; print(json.loads(sys.argv[1])["session_id"])' "$session_json")
curl "$BASE_URL/api/lnurl-auth/check/$session_id"

Best practices

• Always use HTTPS and verify TLS certificates in production.
• Keep client secrets in a secrets manager or environment variables.
• Use PKCE for public clients and rotate secrets for confidential clients.
• Treat LNURL sessions as single-use and enforce short TTLs.
• Validate aud, iss, and exp claims for JWTs.

Advanced features

• Use /oauthx/docs for live OAuth/OIDC API documentation.
• Use /oauthx/status to monitor database and LNURL session health.
• Rotate JWKS keys via the server configuration (JWKS directory + rotation days).

PAYG billing for OAuth clients

Paid API calls are billed per OAuth client_id (agent/app), not per session pubkey. When balance or free quota is exhausted, paid endpoints return HTTP 402 with a Lightning top-up path.

Billing endpoints (OAuth token required)

• POST /api/billing/agent/create-invoice
• POST /api/billing/agent/check-invoice

Example create invoice:

curl -X POST "$BASE_URL/api/billing/agent/create-invoice" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"amount_sats": 1000}'

Example check invoice:

curl -X POST "$BASE_URL/api/billing/agent/check-invoice" \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"invoice_id": "your_invoice_id"}'

402 response shape

When a paid endpoint is called with insufficient balance, expect:

{
  "ok": false,
  "error": "payment_required",
  "code": "PAYMENT_REQUIRED",
  "client_id": "your_client_id",
  "cost_sats": 1,
  "balance_sats": 0,
  "create_invoice_endpoint": "/api/billing/agent/create-invoice",
  "hint": "Top up via Lightning PAYG"
}

Supporting files

• scripts/verify_signature.py validates LNURL-Auth signatures locally.
• HEARTBEAT.md describes periodic health checks for the deployment.
• templates/oauth-client.json provides a ready client registration payload.

Optional helper script

Use scripts/verify_signature.py to validate LNURL signatures locally. Install the dependency first:

python -m pip install ecdsa
python scripts/verify_signature.py --k1 <hex> --signature <hex> --pubkey <hex>