[agl]

By selecting primitives designed for hardware (AES and GHASH) rather than primitives that use operations that are commonly applicable (ChaCha20 and Poly1305), we've ended up with extra hardware to support AES and GHASH. But it's not clear that was actually a good idea, or just path dependence.

ChaCha20, Poly1305, BLAKE2 benefit from improvements that benefit a wide-range of applications, while SHA-3, AES and GHASH do not. Thus the "cost" of high performance support for the former can be amortised over a much wider base.

[aicez]

I suspect that the extra hardware support is not a major concern. This might be because any company that has a true security concern will eventually need to designated an area on its silicon for cryptographic purposes. This area will be security hardened to protect against any side-channel attacks.

Also, sharing HW resource for cryptographic purposes is not possible for any device that needs to pass certain security certification.

Edit: Typo and additional comment

[tptacek]

It's already a problem. The most popular authenticated encryption construction is AES-GCM, which is/was difficult to implement safely on popular mobile platforms because their ARM ISAs required side-channel-prone table-based implementations to be performant. We had to select, in protocols, between Chapoly and GCM to get safety and performance on all those platforms.

Most vulnerabilities in cryptosystems happen in the joinery. Anything we can do to eliminate joinery is going to make our cryptosystems more resilient. Selecting new primitives that will require hardware support to be performant seems like an own-goal.

As someone who has done a number of audits for certified devices, I don't think your statement about shared hardware is accurate. Are you talking about FIPS 140?

[aicez]

That's the reason why I said "suspect" =). I do not claim to know the exact reason for the selection. In any case, the standard is finalized. If you're concern about this being the problem for the next standard which will likely to affect the use of AES-GCM, I suggest you participate in the current cryptographic contest that would target authenticated encryption: CAESAR (https://competitions.cr.yp.to/caesar-submissions.html). I'm not sure how this will affect the overall usage of authenticated encryption in the industry, but this is currently one of the main topics of interest for cryptographic researchers.

"As someone who has done a number of audits for certified devices, I don't think your statement about shared hardware is accurate. Are you talking about FIPS 140?"

Yes. Is my understanding incorrect? I'd like to be informed if this is the case. Thanks.

[tptacek]

There are FIPS certification levels where shared hardware footprint is an issue, but most commercial devices don't need to ship devices with that certification.

I really don't care about what the standards say; thankfully, the important standards, like TLS, aren't bound by what NIST standardizes.