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sctpub.md
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# SCTPub
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Hi! So this is me trying to explain my plans with SCTPub (ActivityPub over SCTP).
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And remember: this is *my* idea, and I don't expect ppl will agree with it, and that's okay! I don't like TLS, doesn't mean I
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refuse to use it.
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First, I'll talk about the choice of SCTP, and the choice of authentication and authorization mechanisms (which are actually
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tightly coupled).
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## Why SCTP?
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SCTP is a little-known protocol, so the idea was to use it to make it more popular and to experiment with it.
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SCTP is in theory capable of seamless proxying such that you can talk to the proxy at the same time as you talk to the target,
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but nothing seems to use this feature. It would still be target-controlled and signed, but the proxy would have some control
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over caching. For sensitive requests, they would go straight through to the server, without the proxy being able to read it.
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This puts the proxy in a position of a semi-trusted middleware. Technically all routers on the internet need to be semi-trusted
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middleware, as any of those routers can track you and target you (e.g. with ads) based on that - see:
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[ALTER (LTE) attack](https://alter-attack.net/), which explains how a middleware can track (fingerprint) the pages you visit.
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Since we already need to somewhat trust the middleware to be able to do anything, we could use that semi-trust state to provide
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more efficient caching. This can be used to a) reduce our server load and b) protect against DDoS attempts. So I guess at this
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point it'd no longer be "pure" SCTP as it'd involve MITM relations between the server and the middleware, but that's okay.
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(I don't think this is the right place to go in-depth into this idea, tho, so I'll stop here. I like to believe mobile
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operators would be happy with the possibility of downscaling their link sizes tho. This can even be used for private content
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e.g. if you have a large chat group you just encrypt the large data (video, etc) and send the group a key, and the data gets
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cached. Crypto is fun.)
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## Words about Authentication
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Registering on SCTPub would require an username and a password, as well as an email address and a display name (handle). The
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username and password never get sent to the server, only the email address and the display name (handle). This means if the
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server is MITMd or malicious or a phishing server is used, the user's identity (login information) is still protected.
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The login interface:
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```
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+-------------------------------------+
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| Login [x] |
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| |
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| Username: _____________ |
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| Password: _____________ |
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| Instance: _____________ |
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+-------------------------------------+
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```
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The registration interface:
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```
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+-------------------------------------+
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| Register [x] |
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| Username: _____________ |
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| Password: _____________ |
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| Instance: _____________ |
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| Email: _____________ |
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| Handle: _____________ |
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+-------------------------------------+
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```
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The authentication is done using a public key mechanism. The Ed25519 private key is generated:
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GO ASK ##crypto @ irc.freenode.net BECAUSE THEY INSIST THAT I'M NOT ALLOWED TO SPECIFY THIS STUFF WHEN TRYING TO MAKE A PORTABLE PROTOCOL
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The user should be able to change their username/password (aka login key). The user may have multiple login keys.
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Once authenticated, the key is to be replaced with a temporary, non-token-based (i.e. no cookies) session key.
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All messages encrypted or signed by the client must include the instance address. All messages received by the instance must
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check the instance address. Nonces must also be used but w/e you probably know this better than me. Encryption vs signing
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should be chosen as needed depending on the requirements (see also *Why SCTP?* above).
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## Words about Authorization
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Authorization should also be done with cryptography, and not OAuth. OAuth is awful. Please don't use OAuth. In fact,
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authorization should be done with public key *encryption*, not even signing. The keys are revokable. The same
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mechanism that allows zero-knowledge authentication can also be used for authorization, as it already provides all of this.
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Authorization doesn't need the session keys mechanism described above. In fact, that mechanism is a form of authorization.
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User agents may optionally authenticate themselves using an UA key. In other words, messages would be double-signed or
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double-encrypted, once by the authorization key, once by the UA key. The authorization key should always be the "inner" key
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while the UA key should always be the "outer" key. (e.g. UA signatures also sign the authorization signature.)
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This shouldn't be used by client-side UAs like mobile apps or web browsers.
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- - -
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Now that we have some of the security aspects out of the way, let's talk about the community aspects: moderation, interaction,
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friendship, etc.
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## Communities
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One of the goals of SCTPub is to provide for *communities*, something we lost a long time ago with the downfall of forums.
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Y'know, like phpBB and stuff.
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As such SCTPub *actively encourages* you to have different accounts on different intances, by not only making it easy to do
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so (with the standard User Agent providing an easy way to sign up to other instances), but also through "dark patterns"
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(sorry). The main dark pattern is that while ppl can boost your content to other instances' main feeds (separate from your
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self-curated feed, more similar to the mastodon "Local Timeline" but including all interactions from local users - boosts,
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etc), but you can't post on other instances like this. Ppl from other instances can choose to follow you, and your content
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shows up to them, but it's not the same as being in the community. Think like Reddit, but each instance is a different sub.
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While there's no technical mechanism to encourage instances to have different rules, I do believe in different instances
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having unique rules but still federating together. This would also support this "communities" model, and encourage multiple
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accounts.
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## Moderation
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One of the things I miss a lot from the time we had forums is moderation. Back in the day, some forums, as elitist as it may
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be, would require you to participate in a closed-off area before participating in the rest of the community. While I'm not
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totally a fan of that idea, I do think a similar idea is warranted: participating locally before federating. This doesn't
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(on its own) reduce spam on a local level, but it helps a lot on a federated level. The software *should* still allow
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instances to opt into a pre-approval stage where you don't even interact with the locals, tho.
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Additionally, to register on other instances, some metadata would be sent across servers. This metadata would be composed
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of the originating instance, the target instance, and it would be signed by the user's login key. This metadata is then
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used to build a chain of trust (web of trust?) of sorts. Also, because you have to sign it, you actually have full control
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over which instances/accounts know about your other accounts.
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Depending on the chain of trust model of each instance, you'd either have to go through the moderator-approval stage on the
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other instance, or it'd trust you because N other instances trust you, or because N instances on its trusted instances list
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trust you, or [...]. There's a lot of flexibility here.
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This chain of trust can also be stored, and retrieved at login time, allowing for smooth login across many instances (see
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Communities above). If one of your instances is down, that's no big deal - just login on another! I don't have many
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accounts across the fediverse because of how hard it is to manage them, but this alone would make it a lot easier.
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Moderation requests (e.g. reports) should definitely federate, altho I haven't worked out all of the details with this.
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## Interactions
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This is a tricky one to explain, because I'm not trying to make another Twitter or Facebook. So bear with me for a second.
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Twitter and Facebook have an attention-based model. On Twitter and Facebook you're "supposed" to make posts that bring you
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attention, like memes or shitposts or flame wars. Reddit also encourages this to a slightly lesser extent. This is NOT
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something I want, even if they're "technically" interactions. (besides, [there's an xkcd for that](https://xkcd.com/1475/))
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Instead, we should look at forums. In forums, there's no pressure to have the most shared content. Instead there's pressure
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to have the most talked about content. That's what I want when I talk about interactions. I want ppl to talk to me, not
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just share my posts. Social isolation is awful, and altho liking and sharing do have their place as forms of non-verbal
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communication (and I'm not proposing we remove them), they just aren't always enough.
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I want to bring back that cozy feel of forums, while taking it to the next level. The federated nature of the fediverse
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allows for ppl to easily interact with eachother, which brings us one step closer to taking it to the next level.
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(I could go on about this all day, but I'm really starving and I'd like to finish this ASAP so I can go eat. it's getting
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hard to stay focused now.)
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## Friendship
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Friendship is important, so just allowing interactions across instances while providing a cozy feel isn't enough.
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So there should be a way to keep up with your friends, and putting some emphasis on it. But I don't think it should be the
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default.
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Both Facebook and Twitter have this thing where you can follow ppl. And then you follow too many ppl and it just goes too
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fast. You can still follow ppl, and it should be encouraged, and there should be lists like in mastodon (or how reddit used to
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have multireddits?) so you can organize things better, but the local timeline, which should be cozy, should be the default.
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(Big instances should be discouraged, while subject-specific/topical instances should be encouraged.)
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- - -
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Okay I'm too hungry to keep going. Cya another time tho. o/
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Sorry that this was so long. I needed to write it down somewhere.
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You can boost and send comments on the associated ActivityPub post: <https://cybre.space/@SoniEx2/101557574984189610>
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@ -0,0 +1,232 @@
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# Connection Latency
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Hi! Let's say you go to visit your favorite website, and it takes 3 seconds to show up. You run a speed test, and your
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connection is doing fine at around 100 Mbps. So how come it took 3 seconds to show up? That's what connection latency is.
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Let's say our network has 3 nodes:
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```text
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your phone ---------> our router ---------> the server
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<--------- <---------
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```
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(This is a rather simplistic model, real networks are a lot more complicated. But it'll work for this demonstration.)
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Let's say sending a packet between two adjacent nodes takes n seconds. This means that for a packet to go from you to
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the server, it takes 2\*n seconds (n seconds to go from you to our router, then another n to go from our router to the
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server). As such, we want to keep this n very low. Ideally, it'd be 0, but in practice we're limited by things like the
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speed of light.
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```text
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your phone ---------> our router ---------> the server
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<--------- <--DATA---
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your phone ---------> our router ---------> the server
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<--DATA--- <---------
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```
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So you might be thinking, "it takes 3 seconds for the server to send me the page?! n is 1.5s?!" No, not quite.
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Before the server can send you anything, it first needs to know what you want. You need to tell the server what you want.
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So our n is no longer 1.5s but 0.75s instead.
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```text
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your phone ---HTTP--> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---HTTP--> the server
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<--------- <---------
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your phone ---------> our router ---------> the server
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<--------- <--DATA---
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your phone ---------> our router ---------> the server
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<--DATA--- <---------
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```
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But that's not all! You can't just ask the server to send you stuff and have it send you stuff! There are things like
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spoofing that we need to be concerned about, otherwise we'd get massive DDoS amplification attacks! Instead, meet TCP:
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## TCP Connection
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Transmission Control Protocol, or TCP, is the protocol used to prevent evil hackers from bringing down the internet. It
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accomplishes that by employing a 3-way handshake. So, how does it work? Well, first, you ask for a connection. This is
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called a SYN in TCP:
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```text
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your phone ---SYN---> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---SYN---> the server
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<--------- <---------
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```
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This lets the server know you want to send data.
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When the server receives the SYN, it then tells you that it got the SYN, and asks *you* for a connection. This is called
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a SYN-ACK:
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```text
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your phone ---------> our router ---------> the server
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<--------- <-SYN-ACK-
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your phone ---------> our router ---------> the server
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<-SYN-ACK- <---------
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```
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This lets you know the server wants to send data, and acknowledges that you want to send data. But we're not quite done yet.
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We still need to acknowledge that the server wants to send data. So, we send an ACK:
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```text
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your phone ---ACK---> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---ACK---> the server
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<--------- <---------
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```
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*Now you can get your data.*
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We took 6n to get a connection, and 2n to get our data... and another 2n to request the data. As such, 10n = 3s, or
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n = 0.3s... So if we were to simply send a packet to the server and get a similar packet back, it'd take about 1.2s. However,
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we're not quite done yet. Before your phone can talk to the server, it needs to know where the server is. When you type an
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address into the browser's address bar, that's only the name of the server - we need instructions to get the packets there.
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This is where DNS comes in:
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## DNS Queries
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Domain Name System, or DNS, is the protocol that takes a domain name and converts it into an IP address - the latter is
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basically a map/instructions on how to get the packets to the destination.
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Thankfully, DNS is usually stored in the router. Additionally, it doesn't use TCP, so there's no 3-way handshake.
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```text
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your phone ---NAME--> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---------> the server
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<---IP---- <---------
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```
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If the router doesn't know a name, it has to ask another router about it. However, this generally only happens once every few
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hours, so it's not something we have to worry about.
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This adds another 2n to our time. We're up to 12n = 3s, or n = 0.25s. It only takes 1 second to send a packet to the server
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and get it back! TCP is awful! ... Not so fast, tho. You might've noticed that the network is busy with only one packet at a
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time. Maybe we can do something to improve this. Okay, we can't improve the DNS query, as it's required to happen before we
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can do anything. But can we improve the TCP? What if we terminate the TCP at the router?
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## Terminating the TCP at the router
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While not strictly allowed by the internet specifications, it's not strictly disallowed either. If implemented, our flow can
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look like this:
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```text
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your phone ---NAME--> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---------> the server
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<---IP---- <---------
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your phone ---SYN---> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---SYN---> the server
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<-SYN-ACK- <---------
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your phone ---ACK---> our router ---------> the server
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<--------- <-SYN-ACK-
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your phone ---HTTP--> our router ---ACK---> the server
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<--------- <---------
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your phone ---------> our router ---HTTP--> the server
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<--------- <---------
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your phone ---------> our router ---------> the server
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<--------- <--DATA---
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your phone ---------> our router ---------> the server
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<--DATA--- <---------
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```
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We're down from 12n to only 9n! With our n = 0.25s, we've shaved off 0.75s from our original 3s! This is a noticeable
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improvement.
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However, you might've noticed I've been talking about `HTTP` so far. Additionally, you can have both an ACK and an HTTP in
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transit at the same time, this shaves off 1n from both our original 12n and our 9n, so we have 11n = 3s and an improvement
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of approximately 0.81s. So it's even slightly better.
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HTTPS, on the other hand, also has its own handshake after TCP's. I don't wanna get into this, because you can probably see
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how ridiculous it's getting by now. This handshake can also be partially terminated by the router, so *it* can also be
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optimized slightly, and we can shave off more n's.
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But let's look at QUIC real quick:
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## QUIC
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(I don't know what QUIC stands for.)
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QUIC is a protocol that does something similar to TCP, with one major difference: it uses UDP.
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User Datagram Protocol, or UDP, is also used by DNS (see above). This means it has no handshake. QUIC implements its own
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handshake, on top of UDP. This means QUIC is basically like TCP, but it comes with a serious caveat: being UDP-based, it
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DOESN'T benefit from our TCP optimization from earlier!
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As such, going QUIC over existing networks has one serious drawback: it adds back those 3n that we were able to shave off!
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And if we optimize for QUIC in addition to TCP, we still only manage to shave off those 3n again.
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So, is there any room for improvement? Can we shave off more n's?
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... Maybe. It would require some changes to the web. More specifically, what if the router could serve some of the content
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directly, without ever reaching the server?
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That's where we need to change the protocols slightly:
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## Terminating "HTTP" at the router
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Rather than terminating just TCP at the router, can we go one step further?
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Can we create a protocol such that the great majority of the connections look more like this:
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```text
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your phone ---NAME--> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---------> the server
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<---IP---- <---------
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your phone ---SYN---> our router ---------> the server
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<--------- <---------
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your phone ---------> our router ---SYN---> the server
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<-SYN-ACK- <---------
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your phone ---ACK---> our router ---------> the server
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<--------- <-SYN-ACK-
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your phone --NHTTP--> our router ---ACK---> the server
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<--------- <---------
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your phone ---------> our router ---------> the server
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<--DATA--- <---------
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```
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(shave off another n if you combine the ACK and the NHTTP)
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We just managed to shave off another 2n! While this requires extensive changes to the existing infrastructure, the load
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times go from the 2.25s/2.19s from our "Terminating TCP at the router" to an even lower 1.64s! This is almost half the
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original 3s! However, this improvement is not as perfect as our "Terminating TCP at the router" and "Partially terminating
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HTTPS at the router" - you want your private data to go encrypted all the way to the server, so anything dealing with
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private data would be back to the original 3s/2.25s/2.19s depending on optimizations. This is okay tho, as most data on the
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web - images, videos, HTML (page layout/behaviour), CSS (also page layout), Javascript (also page behaviour) - are generally
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not private. For example, your neighbor probably watches the same videos as you - thus the videos are not private - but your
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bank statement is exclusive to you - and as such, private.
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|
||||
- - -
|
||||
|
||||
You can boost and send comments on the associated ActivityPub post: <https://cybre.space/@SoniEx2/101563377232093475>
|
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Reference in New Issue