I felt that Apple's description of the initial key setup between the enclave and the main processor was hand-wavy at best. I know of another similar implementa

I felt that Apple's description of the initial key setup between the enclave and the main processor was hand-wavy at best. I know of another similar implementation that's used by Microsemi for their FPGA-based secure boot process[1]. They claim to protect the initial AES key transmission using an "obfuscated" crypto library that is sent to the processor over SPI on boot[2]. Also, I wonder if Apple exchanges a nonce during the setup to prevent replay attacks? [1]: https://www.microsemi.com/products/fpga-soc/security/secure-boot https://www.microsemi.com/products/fpga-soc/security/secure-... [2]: It's a C/C++ library called WhiteboxCRYPTO. There is a whitepaper (http://soc.microsemi.com/interact/default.aspx?p=E464 http://soc.microsemi.com/interact/default.aspx?p=E464), but AFAIK the gist of their argument is that the code and keys are sufficiently obfuscated to prevent reverse engineering (typical marketing-speak).