Amiibo

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Amiibo are NFC figures made by Nintendo, used in games in different forms (different in each game). It can be used with the New3DS and the Old3DS with an IR peripheral.

Technical specifications

See also here.

Specifications can be found on this image, which is a compilation of screenshots made by scanning a Samus amiibo with the Android App "NFC TagInfo": Amiibonfctaginfo.png

Most of the NFC pages are encrypted. This includes the actual Mii data for the owner, an UTF-16 string for the Amiibo nickname, etc.

The NFC tag for Amiibo is NTAG215.

Each page is 4-bytes, the following is the structure of the NFC page:

NFC page Total pages Raw byte offset in EEPROM Total byte size Description
0 4 0x10 0x10 Same as standard NTAG215: 9-byte serial-number, "internal" u8 value, two lock bytes then the "Capability Container (CC)" page.
4 8 0x10 0x20 SHA256-HMAC over 0x1DF-bytes: first 3-bytes are from the last 3-bytes of page[12], the rest is over the first 0x1DC-bytes of the plaintext data following this hash(see page[13]).
12 1 0x30 0x4 Unknown. Last 3-bytes here are used with the above HMAC.
13 0x34 The system crypts 0x1A0-bytes starting here.

Structure of plaintext data from page13

Offset Size Description
0x0 0xB0 Amiibo settings are stored within here.
0xB0 0xD8 AppData, for the user-application with the programID specified in the above Amiibo settings. The data stored here is application-specific.
0x188 0x18 Not used in "decrypted" form, since this isn't encrypted to begin with.

Structure of Amiibo settings

Offset Size Description
0x0 0x20 ?
0x20 0x60 Owner Mii.
0x80 0x8 Application programID for the AppData, zero otherwise.
0x88 0x4 ?
0x8C 0x4 ?
0x90 0x20 Probably a SHA256-HMAC hash.