Few calls.
Any platform.

# 1. Reader reads NTAG424 DNA NDEF payload
#    Fields: epk (encrypted private key), df2 (DEK fragment 2), mode (STD|HS)

# 2. DEK reconstruction
dek = df1_from_config XOR df2_from_badge

# 3. Decrypt badge private key
badge_privkey = AES_CBC_decrypt(dek, epk)

# 4. Request challenge from backend
challenge = POST identity_tag/it_request_challenge
#    { node_uid, badge_uid, tenant_id }

# 5. Sign challenge with badge key (Ed25519)
signature = ed25519_sign(badge_privkey, challenge_nonce)

# 6. Verify at backend
result = POST identity_tag/it_verify_badge
#    { challenge_id, signature_b64 }  ->  { granted: true }

# 7. Reader actuates relay (GRANTED) or displays DENIED

// identity_tag package - badge provisioning
final writer = IdentityTagWriter(api: tagApi);

// Generate badge keypair and encrypt private key with split DEK
final payload = await writer.prepareBadgePayload(
  tenantId  : tenant.id,
  mode      : BadgeMode.STD,   // or BadgeMode.HS
  nodeUid   : null,              // required for HS mode
);

// Write NDEF to NTAG424 DNA via flutter_nfc_kit
await writer.writeToTag(payload);

// 1. Init — JWT identity, silent on subsequent boots
final auth = IdentityAuthServiceStd(ITEMSGlobals.authURI);
await auth.ensureJwt(
  preferredLocale: locale.languageCode,
  utcOffsetMin:    DateTime.now().timeZoneOffset.inMinutes,
);

// 2. Handshake — silent if identity already present on device
final result = await api.mjHandshake(
  identityHash: identityHash,
  publicKey:    publicKey,
);

// 3. Store JWT — session active, no password, no credential database
await _storage.write(key: 'token', value: result['token']);

// 4. Every request — AES-256-GCM payload, end-to-end encrypted
final response = await api.postEncrypted({'request': 'your_request'});

dependencies:

  # Identity Layer — local packages, no external registry
  identity_package:
    path: packages/identity_package
  identity_std:
    path: packages/identity_std
  identity_hs:
    path: packages/identity_hs
  items_crypto:
    path: packages/items_crypto

// 1. Include the Identity Layer bridge — 5 KB
require_once 'identity/_mj_auth.php';

// 2. Authenticate — JWT verified, identity_hash extracted
//    identity_hash is a 64-char SHA-256 hex — never a user ID
[$identityHash, $tenantId, $claims, $role] =
    mj_authenticate_identity($encoder);

// 3. Every response — AES-256-GCM encrypted, end-to-end
sendEncryptedResponse($encoder, [
    'status' => 'ok',
    'data'   => $yourData,
], ['ts' => time()], 200);

// Requires role = admin — never operator
[$userId, $tenantId, $claims, $role] = mj_authenticate($encoder);
mj_require_role($encoder, $claims, 'admin');

// Register mandate — opens 72h export window
// target_identity_hash: 64-char SHA-256, never plaintext identity
// Ciphertext is never stored — metadata only
$connector->executeDatabaseParameterQuery(
    "INSERT INTO audit_log (mandate_number, issuing_country,
     issuing_court, target_identity_hash, export_status)
     VALUES (?, ?, ?, ?, 'PENDING')",
    [$mandateNumber, $issuingCountry, $issuingCourt, $targetHash],
    $db
);