https://www.trustedkey.com https://www.trustedkey.com actually uses the Enclave and also the equivalent component (Secure Element) in Android phones. Both of t

https://www.trustedkey.com https://www.trustedkey.com actually uses the Enclave and also the equivalent component (Secure Element) in Android phones. Both of these modules use the secp256r1 curve at least, so the signature verification algo which runs on the blockchain can be the same for both types of devices. (You can find some more details on this topic here: http://blog.enuma.io/update/2016/11/01/a-tale-of-two-curves-hardware-signing-for-ethereum.html http://blog.enuma.io/update/2016/11/01/a-tale-of-two-curves-...) Since the Byzantium fork there are some precompiles available for curve operations. Using those for the r1 curve signature verification in EVM code brought down the gas cost to practical levels.