The link makes it sound like SEP only handles TouchID - is this true, or does the SEP also deal with passcodes?
From the [ios security guide]:
> The Secure Enclave provides all cryptographic operations for Data Protection key management and maintains the integrity of Data Protection even if the kernel has been compromised.
e.g. you can encrypt and decrypt, referencing a key by id, but without having the private key ever leave the enclave, even if the app or iOS kernel gets compromised.
[ios security guide] https://www.apple.com/business/docs/iOS_Security_Guide.pdf
The Secure Enclave section is pretty short and the entire document is very approachable.
Several months ago I saw a project making wallet software that used the enclave. I forget who they were but I think they'll have a hard sell; everyone just reflexively assumed it was insecure because it was on a phone.
It's unfortunate people would draw negative connotations from it being on a mobile device. The security architecture of iOS and the SEP combined with the relatively wide deployment of iPhones makes for a great number of use cases.
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-...)
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.