Connect Directory Reference

Directory dependency graph for Connect:

Directories
	main

Files
	config.template.h

Detailed Description

cryptnox-sdk-esp32

ESP32 SDK for managing Cryptnox smart card wallets

Connect — Secure Channel + Card Info

Open the Cryptnox Hardware Wallet secure channel from an ESP32-S3 and read back the card owner's name and email. This is the safest starting point: the firmware never sends a PIN, so it cannot lock the card.

Requirements

Component	Details
Hardware Wallet	Cryptnox Hardware Wallet, initialised (cryptnox init)
NFC reader	PN532 over SPI — MOSI=11, MISO=13, SCLK=12, CS=10 (see hardware setup)
Board	ESP32-S3-DevKitC-1
Toolchain	ESP-IDF v5.5
Repository	Cloned with submodules (git clone --recurse-submodules …)

No PIN, no seed required. Wi-Fi credentials in main/config.h are still mandatory — the radio is started on boot so it feeds the ESP32 hardware TRNG with full entropy before any crypto runs.

Quick start

# from the repository root, after sourcing ESP-IDF env
cd examples/Connect
cp config.template.h main/config.h          # create your runtime config (gitignored)
$EDITOR main/config.h                       # fill WIFI_SSID / WIFI_PASSWORD
idf.py set-target esp32s3                   # once
idf.py build flash monitor

Exit the serial monitor with Ctrl-]. Place the card on the PN532 antenna once the firmware reports PN532 ready.

Expected output

I (520) wifi:wifi driver task: ...
I (1234) connect: Wi-Fi connected, TRNG seeded
I (1280) connect: PN532 firmware 1.6, features 0x07 (MIFARE + ISO-DEP + FeliCa)
I (2410) connect: Card connected, secure channel established
I (2420) connect: Owner name : Alice
I (2421) connect: Owner email: alice@cryptnox.com

How it works

wifi_init() + esp_wifi_connect()    Bring up Wi-Fi → TRNG ready
       │
spi_bus_initialize()                Configure SPI3 host
       │
wallet.begin()                      Reset the PN532, probe firmware
       │
wallet.connect(session)             SELECT + cert chain verify
       │                            (secp256r1) + ECDH + mutual auth
       │                            → session.aesKey / macKey / iv
       │
wallet.getCardInfo(session)         Secured APDU (AES-CBC + MAC)
       │                            Decrypt response, parse name & email
       │
wallet.disconnect(session)          Zero session keys

Step-by-step code

Wire the adapters together (declared once in app_main):

ESP32Logger          logger;
Pn532NfcTransport    nfc(/*pn532*/ &pn532, logger);
ESP32CryptoProvider  cryptoProvider;
ESP32Platform        platform;
CryptnoxWallet       wallet(nfc, logger, cryptoProvider, platform);

Bring up the radio + bus + reader:

ESP_ERROR_CHECK(nvs_flash_init());
wifi_init();                          // brings up Wi-Fi → seeds the HW TRNG
spi_bus_init();
if (!wallet.begin()) {
    ESP_LOGE(TAG, "PN532 init failed");
    vTaskDelay(portMAX_DELAY);
}

Open the channel and read the card in a tight loop:

while (true) {
    CW_SecureSession session;
    if (wallet.connect(session)) {
        CW_CardInfo info;
        if (wallet.getCardInfo(session, &info)) {
            ESP_LOGI(TAG, "Owner name : %s", info.name);
            ESP_LOGI(TAG, "Owner email: %s", info.email);
        }
    }
    wallet.disconnect(session);
    vTaskDelay(pdMS_TO_TICKS(1000));
}

Troubleshooting

Symptom	Cause	Fix
PN532 init failed	Reader wiring / power / mode switches	Check VCC = 3.3 V, the MOSI/MISO/SCLK/CS pinout and the PN532 SPI mode switches (SW0=HIGH, SW1=LOW) — see hardware setup
Wi-Fi never connects	Wrong SSID / password, or 5 GHz-only network	ESP32-S3 supports 2.4 GHz only — verify SSID, password, band in main/config.h
Card not detected or secure channel failed	Card off the antenna, or card not initialised	Bring the card within ~1 cm of the antenna; run cryptnox init if it is a brand-new card
getCardInfo failed (channel error or parse error)	Card initialised without an owner name/email	Re-run cryptnox init and fill in the owner fields

License

cryptnox-sdk-esp32 is dual-licensed:

• LGPL-3.0 for open-source projects and proprietary projects that comply with LGPL requirements
• Commercial license for projects that require a proprietary license without LGPL obligations (see COMMERCIAL.md for details)

For commercial inquiries, contact: conta.nosp@m.ct@c.nosp@m.ryptn.nosp@m.ox.c.nosp@m.om