Arm Limited Vigil Security, LLC Arm Limited This document specifies a firmware update mechanism where the firmware image is encrypted. Firmware encryption uses the IETF SUIT manifest with key establishment provided by hybrid public-key encryption (HPKE) and AES Key Wrap (AES-KW). HPKE uses public key cryptography while AES-KW uses a pre-shared key-encryption key. Encryption of the firmware image is accomplished with convential symmetric key cryptography.