1.1 Use Cases

SHA104-TFLXAUTH is a member of the Microchip CryptoAuthentication family of high-security cryptographic devices that combine world class hardware-based key storage with hardware cryptographic accelerators to implement authentication.

SHA104-TFLXAUTH has a command set that allows for its usage in multiple symmetric key applications. The primary uses include the following:

  • Accessory/Disposable Authentication

    Allows for authentication of accessory and/or disposable system components. For disposable components, the use may be restricted through the use of a monotonic counter.

    • Challenge/Response authentication – Requires a SHA104 on the accessory/disposable side only. SHA104 will be provisioned with a symmetric key, host firmware will embed one or several challenge/response pair(s).
    • Shared Key authentication – Requires integrating a SHA104 on the accessory/disposable and an SHA105 on the host side – both Secure Element will be provisioned with the same symmetric key.
    • Diversified Key authentication – Requires integrating a SHA104 on the accessory/disposable and a SHA105 on the host side. SHA104 will be provisioned with a unique symmetric key derived from a root symmetric key and the SHA104 unique serial number. SHA105 will be provisioned with the root symmetric key.
  • Ecosystem Control and Anti-Counterfeiting 


    Validates that a system or component is authentic and came from the OEM shown on the nameplate.

In typical applications, the SHA104-TFLXAUTH will be used on the accessory/disposable side of an application and the SHA105 will be used on the host side of that application. SHA104-TFLXAUTH can be ordered as either an I2C or SWI I/O option. If an SWI device is implemented in a given application, it can optionally be used in parasitic power mode.
Tip: If it is desirable to not have a PCB or to have a minimal number of signals connected to the accessory/disposable side, then the SHA106 should be considered for the application. This device has an integrated capacitor that allows for a true 2-wire implementation.