Amiibo Encryption Key -

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):

Every Amiibo contains a tiny, passive NFC chip embedded in its base. Nintendo utilizes standard chips manufactured by NXP Semiconductors.

: This file contains the constant data used for the initial decryption of the amiibo's unique ID and basic information. locked-secret.bin amiibo encryption key

The breakthrough came from examining the firmware on the 3DS. In older firmware versions (8.1.0 through 9.2.0), Nintendo hardcoded a normal‑key directly in Process 9 for deriving amiibo encryption keys. This was a critical mistake. In firmware 9.3.0 , Nintendo changed the implementation to use a key scrambler, but the scrambling algorithm was cryptographically weak. Researchers were able to deduce the key scrambler function and, combined with other information, eventually recover the underlying master keys.

: A keyed-hash message authentication code used to verify data integrity. It ensures that the data has not been modified or corrupted. Used to sign the "locked" data of an

Nintendo uses a layered security system to prevent users from easily cloning amiibo or altering their game data. The system relies on two distinct 80-byte master keys:

Unlocking the Vault: The History, Tech, and Legacy of the Amiibo Encryption Key In older firmware versions (8

Used to sign "fixed" information, such as the unique ID (UID) of the chip and the specific amiibo type.

Nintendo did not just write plain text to these chips. They implemented a sophisticated security system using a (Cipher-based Message Authentication Code). Without the correct key, the console cannot verify that the data hasn't been tampered with.