Used to sign the "locked" data of an amiibo, such as its unique ID (UID) and character type. This information is immutable once written to an NFC tag. Data Master Key (locked_secret.bin):
As with many reverse‑engineering endeavours, a delicate balance exists between the rights of the copyright holder and the rights of the user to tinker with lawfully purchased goods. The DMCA’s interoperability exception provides a legal safe harbour for much of this activity, but it is not an unlimited license. The responsible course is to use the acquired knowledge for personal, educational, and non‑commercial projects, respecting both the law and the hard work of the original creators.
Use multiple Amiibo characters without carrying the physical collection.
The amiibo encryption key is more than a single secret; it is an entire ecosystem of cryptographic mechanisms. Built on the foundation of the NTAG215 chip, Nintendo layered AES‑CTR encryption, HMAC‑SHA256 signing, and a UID‑derived password to protect both the identity of the figure and the game data stored on it. The system held up for several years before determined reverse engineers, armed with firmware analysis and knowledge of cryptographic weaknesses, recovered the master keys and made them available to the public. amiibo encryption key
While many users utilize keys to preserve their expensive collections from physical wear and tear, or to access content locked away in out-of-print, scalper-priced figures, it undeniably bypasses Nintendo's monetization model for physical DLC. Summary of the Technical Ecosystem NTAG215 Chip Physical storage medium embedded in the toy. Commercially open UID Unique 7-byte factory serial number on the chip. Read-only, unchangeable Encryption Keys key_retail.bin used to sign and validate data. Proprietary Nintendo IP HMAC-SHA256 Cryptographic math binding the data to the UID. Industry standard
Because amiibo use standard chips, their raw data could easily be cloned if not for Nintendo's security layers.
Password protection (derived from the UID) is used to lock certain memory sectors, preventing users from changing a Kirby amiibo into a Mario amiibo once it has been written. Usage in Custom Amiibo Used to sign the "locked" data of an
Inside that memory dump, the AES key was sitting in plaintext.
With the encryption keys known, the homebrew community created several tools that enable everyone to create, edit, and emulate amiibo tags. The most important of these is , written in C by socram8888. Amiitool expects binary dumps of amiibo data and provides three main operations:
: These keys are copyrighted property of Nintendo. While the software to use them is legal, the keys themselves are rarely hosted on official sites and must be sourced legally from your own hardware. The amiibo encryption key is more than a
By early 2015, prominent developers in the 3DS homebrew scene successfully dumped the console's RAM while it was interacting with an Amiibo. By analyzing the memory footprint during a read/write cycle, they isolated the exact 160-byte binary files containing the proprietary retail and shared keys.
Used to derive keys for signing the internal, hard-coded ID of the NFC chip. How Encryption Works
TagMo is the most popular app for writing Amiibo to blank NTAG215 tags. Obtain the key_retail.bin file.