[vasilvv]

> By the way, does anyone know why QUIC specifically put NewReno as its official congestion control [0]? Different environments benefit from different algorithms so I don't see why.

It's a "reasonable default", in the sense that it normally works quite well, and is easy to implement. The dangerous thing about congestion control is that it's really easy to get it wrong and not notice (as noticing requires performance testing and monitoring).

Google QUIC uses BBR on the server side. I wrote the initial version of said BBR implementation, and it took a lot of effort to get it to a production-ready state, so I would not generally recommend writing BBR from scratch. CUBIC is much simpler than BBR, but is also prone to subtle bugs like [0].

> 2. Not everything that needs encryption needs TLS specifically. TLS is not a one-size-fits-all solution.

I'm actually curious what use cases you have in mind. TLS definitely does not cover 100% of all possible cases, but I've seen a surprising number of cases where people rolled their own thing when using (D)TLS would have just worked.

[0] http://bitsup.blogspot.com/2015/09/thanks-google-tcp-team-fo...

[mmm_grayons]

Thanks for the information; your link was an interesting read.

> I'm actually curious what use cases you have in mind.

TLS certs can be a hassle for peer-to-peer type stuff. I'm currently working on a project that does encrypted file transfer between two people and uses a PAKE instead, because I can encode 32 bits of random data in 3 words and that's plenty versus having to deal with public-key infrastructure or dealing with cert files/large blocks of base64. I don't want to run a CA for this and a self-signed cert doesn't verify identity. I certainly don't want to trust some other CA. SSH sort of solves this problem by keeping a known_hosts file with which IP has which key. Unfortunately, that's only good after first contact. People's IPs also change whereas those of servers usually don't. Finally, I share Colin Percival's concerns about the quagmire of backwards compatibility that TLS has become: https://news.ycombinator.com/item?id=16751358

Edit: What's app also moved from TLS to a protocol based on Noise. I believe the rationale was that it's a much cleaner, ground-up implementation rather than being an evolution of something from the '90s. It's analogous to C++: you can do just about anything with it because it has so many features, but they were bolted-on piecemeal. This also means there are a half-dozen ways to do any given thing and even more ways to do something wrong, so there are stylistic inconsistencies on teams beyond "tabs vs. spaces".

[rstuart4133]

> TLS certs can be a hassle for peer-to-peer type stuff.

From my perspective that's very generous. All the flags and extensions in x509 certs seem to have one use: provide a way for the companies who run the PKI infrastructure to extract more money. I am perhaps to being a little harsh here, as some like the ability to sign sub-certs are absolutely necessary to PKI.

However, outside of PKI, almost none of it adds any security. But they do add enormous amounts of complexity. To take but one example from StrongSwan:

> In addition to serverAuth the 'IP Security IKE Intermediate' EKU with OID 1.3.6.1.5.5.8.2.2 does not hurt either and will allow you to use the certificate with older Mac OS X releases too.

How much does 1.3.6.1.5.5.8.2.2 or indeed any of the extensions add to IPSec security: none. Yet woe betide you if you miss it and someone attempt to use your IPSec implementation from an older OSx. But if you try to work around that by providing every extension under the sun, Windows will reject it. So you end up walking this tightrope of trying to find the magic combination that works with everything.

The option to use TLS without the x509 baggage would be a breath of fresh air.

[tialaramex]

TLS is designed to let you replace the provided peer authentication, people have looked at drafts to hook a PAKE into TLS 1.3 in the past but those drafts have expired. There has more recently been interest in trying again. You can even (though it's discouraged) just make the right noises to get appropriate enumerated values reserved for your mechanism, and ship it, without the hassle (valuable as it would be for actual security) of peers offering their opinions and maybe not doing things how you prefer.

I don't see how certificates are relevant at all? You clearly don't want a certificate if you intend a PAKE to provide mutual assurance of identity.

I think Colin grossly overestimates the chances of some bozo getting an RSA (of all things) transport protocol to work securely. My guess is that most attempts will end without it working at all (frustrating but safe) but a potentially very scary number would work in the sense that they seem to function as intended while not delivering the expected security through a combination of ignorance and inadequate testing. I particularly don't buy that a bozo who actually does get all that right can't instead write code against OpenSSL without ripping a hole in the universe. I don't like OpenSSL, but even I can see that it gets enough hard things right to be a useful contribution.

[mmm_grayons]

There is already an older PAKE in TLS, TLS-SRP. It doesn't apear to be well-loved [0] and I don't know enough about the IP situation to use it confidently, so I've been looking through the CFRG reviews on PAKE candidates [1] to get more info.

I mentioned certs because they're a pain to manage and are generally how people do TLS, though there are a few PSK options [2].

Your right that implementing a secure RSA protocol by one's self is difficult. That's the idea of things like Noise, to make messing up your own protocol implementation harder (albeit not impossible). The other option is building on something like libsodium that has a good, well-documented API and is hard(er) to screw up.

TLS certainly works for a lot of things, it just doesn't work for everything. For that reason, something that bakes it in probably won't replace TCP.

[0]: https://blog.cryptographyengineering.com/should-you-use-srp/

[1]: https://github.com/cfrg/pake-selection

[2]: https://tools.ietf.org/html/rfc4279

[tialaramex]

You can't use the stuff you linked with TLS 1.3, and of course you can't use an older TLS version in QUIC. It's possible you knew those things, but I want to make sure.

My recent experience with the password manager that was linked on HN shows me that even an abuse-resistant API like Sodium cannot stop people being idiots. (The author believs some random passwords aren't "unique enough" so they have written a bunch of code on top of Sodium to avoid passwords like '4K2m_chmJ$gD' which they feel wouldn't be suitable because it has the letter 'm' more than once...)

[mmm_grayons]

I hadn't checked compatibility and wasn't aware they no longer included SRP. It's not the best PAKE, but to my knowledge, not cryptographically broken (Apple uses it for a bunch of stuff, IIRC). Thanks for letting me know.

And you're right, that's pretty dopey with the password manager. I understand the point of password security measures, but just do something like pam cracklib. There's no such thing as an idiot-proof library. Honestly, that looks like the developer was being kind of lazy, using a constant size for things like max password length.

My only point here is that there are libraries that are well-tested, secure, and at least as idiot-proof as openssl. The increased ability to do the protocol wrong with something like libsodium is balanced by the increased ability to do the crypto wrong with something like openssl.

[tialaramex]

They didn't explicitly deprecate TLS-SRP, it simply can't work in TLS 1.3 because although it superficially looks like a minor revision, and indeed (to defeat middlebox ossification) on the wire it appears to say it is only TLS 1.2 in reality it's a fairly radical change.

TLS-SRP bolts over the traditional TLS key exchange mechanism, which made sense, but in TLS 1.3 that entire mechanism is gone, keys are either pre-shared or they're always agreed in the first protocol burst using an (elliptic curve) Diffie Hellman method. So by the time you'd have a natural opportunity to do SRP the protocol has already agreed keys anyway.

[thayne]

If you are in a situation where you can have a shared key, TLS, with it's asymmetric handshake is probably overkill.

[tialaramex]

You can do TLS with shared keys. The rest of this comment describes the situation in TLS 1.3 since earlier versions are not used in QUIC and future versions don't exist yet.

If you want Forward Secrecy you still need to do the DH steps so that you'll get unique session keys, but you don't need a certificate since your mutual knowledge of the shared key is sufficient.

If you don't need Forward Secrecy (pro tip: You actually do, but I can't stop you) then you can skip DH and just go straight to the main course.