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.
Tag information #
- Model: 🔗 NTAG215
- Manufacturer: NXP Semiconductor
- Page size: 4 bytes
- Page count: 135 pages (540 bytes)
- Data pages: 126 pages (504 bytes)
Page layout #
Excluding the auth-related configuration pages at the end, the structure of the NFC pages is the following:
| NFC page | Total pages | Raw byte offset in EEPROM | Total byte size | Writable | Description | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0x0 | 0x3 | 0x0 | 0xC | No | Standard NTAG215: 9-byte serial-number, "internal" u8 value, then the two lock bytes which must match raw binary "0F E0". | ||||||||||||
| 0x3 | 0x1 | 0xC | 0x4 | No | Standard NTAG215: "Capability Container (CC)". Must match raw binary "F1 10 FF EE". | ||||||||||||
| 0x4 | 0x1 | 0x10 | 0x4 | Yes | Last 3-bytes here are used with the following HMAC where the size
is 0x1DF-bytes. The u16 starting at byte1 is used for the first two
bytes in the 0x40-byte input buffer for Amiibo crypto init.
| ||||||||||||
| 0x5 | 0x8 | 0x14 | 0x20 | Yes | The system crypts 0x1A0-bytes with some data from here, see below. | ||||||||||||
| 0xD | 0x8 | 0x34 | 0x20 | No | SHA256-(HMAC?) hash. The first 0x18-bytes of this hash is section3 in the encrypted buffer. | ||||||||||||
| 0x15 | 0xB | 0x54 | 0x2C | No | This is plaintext data, see below. | ||||||||||||
| 0x20 | 0x8 | 0x80 | 0x20 | Yes | SHA256-HMAC hash over 0x1DF-bytes: first 3-bytes are from the last 3-bytes of page[4], the rest is over the first 0x1DC-bytes of the plaintext data. | ||||||||||||
| 0x28 | 0x45 | 0xA0 | 0x114 | Yes | This is section1 in the encrypted buffer. | ||||||||||||
| 0x6D | 0x15 | 0x1B4 | 0x54 | Yes | This is section2 in the encrypted buffer. | ||||||||||||
| 0x82 | 0x1 | 0x208 | 0x4 | No | Standard NTAG215: first 3-bytes are dynamic lock bytes. Must match raw binary "01 00 0F". | ||||||||||||
| 0x83 | 0x1 | 0x20C | 0x4 | No | Standard NTAG215: CFG0. Must match raw binary "00 00 00 04". | ||||||||||||
| 0x84 | 0x1 | 0x210 | 0x4 | No | Standard NTAG215: CFG1. Must match raw binary "5F 00 00 00". |
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”:
See here regarding the Amiibo encryption.
Data structures #
Structure of the data starting at page 0x15 #
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x8 | Amiibo Identification Block |
| 0x8 | 0x4 | ? |
| 0xC | 0x20 | Probably a SHA256-(HMAC?) hash. |
Structure of Amiibo Identification Block #
| Offset | Size | Description | Notes |
|---|---|---|---|
| 0x0 | 0x2 | Game & Character ID | First 10 bits are the Game ID and last 6 bits are Character ID. |
| 0x2 | 0x1 | Character variant | |
| 0x3 | 0x1 | Amiibo Figure Type | |
| 0x4 | 0x2 | Amiibo Model Number | |
| 0x6 | 0x1 | Amiibo Series | |
| 0x7 | 0x1 | Format Version | Always 0x02 |
Encrypted data buffer structure #
| Encrypted buffer offset | Raw byte offset in NFC EEPROM | NFC page | Byte size | Notes |
|---|---|---|---|---|
| 0x0 | 0x14 | 0x5 | 0x20 | |
| 0x20 | 0xA0 | 0x28 | 0x114 | |
| 0x134 | 0x1B4 | 0x6D | 0x54 | |
| 0x188 | 0x34 | 0xD | 0x18 | This data is included in the crypto buffer, even though this data isn’t actually encrypted(this is part of a hash). |
Structure of the plaintext data #
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0xB0 | Amiibo settings are stored within here. |
| 0xB0 | 0xD8 | AppData, for the user-application specified in the above Amiibo settings. The data stored here is application-specific. The data stored here is normally all big-endian, even when the user-application is only for 3DS systems. Note that this data is initially uninitialized, and at least some of it will stay that way unless an application clears/initializes *all* of it. |
| 0x188 | 0x18 | Not used in “decrypted” form, since this isn’t encrypted to begin with. |
Structure of Amiibo settings #
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x1 | Flags. The low 4-bits here are copied to the struct used with NFC:GetAmiiboSettings. The below setup date is only loaded when bit4 and/or bit5 here are set, otherwise value 0 is used instead for the date. Bit4=1 indicates that the Amiibo was setup with amiibo Settings: NFC:GetAmiiboSettings will return an all-zero struct when this is not set. Bit5=1 indicates that the AppData was initialized. NFC:InitializeWriteAppData will return an error if this is value 1, when successful that command will then set this bit to value 1. |
| 0x1 | 0x1 | Country Code ID, from the system which setup this amiibo. This is copied to the struct used with NFC:GetAmiiboSettings. |
| 0x2 | 0x2 | This big-endian u16 counter is incremented each time that the CRC32 at offset 0x8 gets updated by NFC:InitializeWriteAppData, due to that value not matching the calculated one. When this value is already 0xFFFF, this counter won’t be updated anymore. |
| 0x4 | 0x2 | u16 big-endian date value, see below. This is the date for when the Amiibo was initially setup in amiibo Settings. This is also written by NFC:InitializeWriteAppData. |
| 0x6 | 0x2 | u16 big-endian date value, see below. This is the date for when the Amiibo was last written to. |
| 0x8 | 0x4 | Big-endian CRC32 value with initialval=~0, with the 8-byte output from Cfg:GenHashConsoleUnique. This is written by NFC:InitializeWriteAppData, when the current value doesn’t match the calculated one. |
| 0xC | 0x14(10*2) | UTF-16BE Amiibo nickname. |
| 0x20 | 0x60 | Owner Mii. |
| 0x80 | 0x8 | Big-endian application programID/titleID from the application which initialized the AppData, zero otherwise. This is only written, not compared with the user application titleID: doing the latter would break games’ cross-platform compatibility with 3DS<>Wii U(Super Smash Bros 3DS/Wii U for example). |
| 0x88 | 0x2 | u16 big-endian. This value is incremented each time the Amiibo is written to. When this value is already 0xFFFF, this counter won’t be updated anymore. |
| 0x8A | 0x4 | Big-endian u32 Amiibo AppID. |
| 0x8E | 0x2 | ? |
| 0x90 | 0x20 | Probably a SHA256-HMAC hash. |
Format of the big-endian date values:
| Bit | Description |
|---|---|
| 0-4 | Day |
| 5-8 | Month |
| 9-15 | Year, relative to 2000. |
3DS read/write procedure #
Note this is the procedure used by the console, but isn’t the only way of reading them.
Read procedure #
- GET_VERSION
- READ, startpage=0x03.
- PWD_AUTH. Key is based on UID.
- FAST_READ: startpage=0x00, endpage=0x3B
- FAST_READ: startpage=0x3C, endpage=0x77
- FAST_READ: startpage=0x78, endpage=0x86
Therefore, *all* pages from the Amiibo NFC tag are read, including the configuration pages at the end.
Write procedure #
- GET_VERSION
- READ, startpage=0x03.
- PWD_AUTH. Key is based on UID.
- Multiple WRITE commands for writing to pages 0x04..0x0C. The first byte for page[4] is zero here.
- Multiple WRITE commands for writing to pages 0x20..0x81.
- Use the last 3 commands from the above reading section.
- WRITE: page=0x04, same data as before except first byte is 0xA5 this time.
- FAST_READ: startpage=0x04, endpage=0x04
Games using Amiibo AppData #
The following is a list of games which actually store game-specific data on Amiibo, not *just* using Amiibo for checking character IDs:
| Name | Available for (New)3DS | Available for Wii U | Amiibo AppID | AppData structure / link to info | AppData modification for exploitation notes. |
|---|---|---|---|---|---|
| Super Smash Bros | Yes | Yes | 0x10110E00 | 🔗 1 | No crash ever triggered via AppData fuzzing. |
| Mario Party 10 | No | Yes | ? | N/A | N/A |
| Animal Crossing: Happy Home Designer | Yes | No | 0x0014F000 | N/A | The initial AppData handling doesn’t appear to have any vuln(s), going by manual code-RE for update v2.0. Fuzzing wasn’t attempted. |
| Chibi-Robo!: Zip Lash | Yes | No | 0x00152600 | The entire AppData is read by the game, but only the first 0x10-bytes are actually used. | No crash ever triggered via AppData fuzzing. |
| Mario & Luigi: Paper Jam | Yes | No | 0x00132600 | Starts with the process-name(“MILLION”). The rest seems to be bitmasks maybe? | No crash ever triggered via AppData fuzzing, when viewing “character cards”(just unlocks various cards). |
| The Legend of Zelda: Twilight Princess HD | No | Yes | 0x1019C800 | Unknown. | No crash/hang ever occurred when using amiibo in-game for “Cave of Shadows”. With the amiibo quick-start option at the title-screen, only errors ever occurred( |