NFC Functionality

NFC Overview

The Snake-V1 leverages the Near Field Communication (NFC) capabilities to interact with high-frequency (13.56 MHz) RFID tags and devices. This module allows users to scan, read, and emulate various NFC protocols, making it a versatile tool for security auditing and peripheral testing.

Key Features

• UID Reading: Capture the Unique Identifier (UID) of ISO14443 and ISO15693 compliant tags.
• Tag Data Extraction: Read data blocks from common tag types (Mifare Classic, Ultralight, NTAG).
• Emulation: Emulate previously saved or manually entered UIDs to test card readers.
• Protocol Analysis: Support for ISO14443A/B, FeliCa, and ISO15693 standards.

Usage Guide

Reading a Tag

To read an NFC tag, navigate to the NFC menu on your Snake-V1 and select Read.

1. Place the back of the Snake-V1 near the NFC tag or card.
2. The device will automatically detect the protocol and display the UID.
3. If the tag is a known type (e.g., Mifare Classic), the device will attempt to read available sectors.

# Typical terminal output during a read operation
[NFC] Searching for tags...
[NFC] Found ISO14443A Tag
[NFC] UID: AB 12 CD 34
[NFC] ATQA: 00 04
[NFC] SAK: 08

Emulating a Tag

Emulation allows the Snake-V1 to act as a passive NFC tag.

1. Select Emulate from the NFC menu.
2. Choose a saved dump file or select Manual Entry to input a specific UID.
3. Hold the Snake-V1 against the reader you wish to test.

[!NOTE] Emulation performance can vary based on the reader's signal strength and the antenna alignment of the Snake-V1.

Writing and Saving

You can save captured tag data to the microSD card for later analysis or emulation.

1. After a successful read, select Save.
2. Provide a filename via the on-screen keyboard or CLI.
3. The data is stored in a standard .nfc format, compatible with the Snake-V1 ecosystem.

Supported Tag Types

The following tag types are currently supported for interaction and testing:

| Type | Reading | Writing | Emulation | | :--- | :---: | :---: | :---: | | ISO14443A (Mifare) | Yes | Yes | Yes | | ISO14443B | Yes | No | Yes | | ISO15693 (NFC-V) | Yes | Yes | No | | FeliCa (NFC-F) | Yes | No | No | | NTAG 21x | Yes | Yes | Yes |

Technical Specifications

• Frequency: 13.56 MHz.
• Controller: Integrated NFC subsystem compatible with STM32WB series.
• Antenna: Internal PCB loop antenna optimized for short-range proximity (0–3cm).
• Data Rates: Supports 106, 212, 424, and 848 kbps depending on protocol.