IPFS Weekly Call, 27 May 2019

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From YouTube: IPFS Weekly Call - 2019-05-27

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IPFS Newsletter: https://tinyletter.com/ipfsnewsletter

Peergos.org - is your data secure?

A

Hello, hello, hello,.

B

Okay, this will start streaming soon.

B

I can hear myself I think it's working.

B

All right, let's start recording.

B

Hello, everyone and welcome to the ipfs weekly call. This call where we're able to see the cool stuff that people are doing in the ipfs community and today, we'll get right into it. I am Preston from Pierre. Ecos is going to tell us about his project, which is Yui, p2p storage, so we'll learn about how he's using IPS and we'll learn more about this really interesting project, so we're just gonna get right into it, and I am Preston or dr. Kristin. If you can start sharing that'd be great.

B

Thank you good, yes, sweet.

B

C

C

Is your data secure? Sadly, for most people, the answer is no, so as a portraitist and I'm going to introduce you to ping us and tell you how we do what we do and why, but first, let's start with some motivation. So what do we have? What am I trying to do? What we're trying to do with VMs I want to store my files online, but without Dropbox being able to read them.

C

I want to be able to share my photos, so they could leave it without facebook scene and I only bare-assed, all my files somewhere, but not in a company that could go bankrupt, dig a little deeper. We can split our desires into three main categories.

C

The first one is security, so we want a safe login and also that means was a lot of you mean in a decentralized system, strong crypto, ideally post quantum, you wanna hide file, metadata like names and sizes and directory structures, and we want to be independent of the TLS certificate authorities and DNS.

C

Thankfully, ipfs makes the last two quite easy. The second main category is control. How we want to be self host of all again I'd, be fair, solves most of the hard problems there we're going to be able to selectively share files now with fine-grained access control.

C

We don't know exploded that to anyone, not even the service provider by that I mean the storage, promote and we'll treat you darkness, so no need to put in a phone number or even an email address. And finally, if you want anyone to actually use it, it has to be convenient, and these days convenience means a web interface. So you should be able to log in from any device should have easy file syncing across devices. You should be able to publish files to people who are not users of the network now in an easy way.

C

Essentially, it should be as convenient as Dropbox or Facebook, so style control. The overall architecture we have here we have ipfs, as we know, is that is a Content address. Data store the mapping from either TNS or para. Color to it is basically mapping for public key to a hash. We use I've been s itself yet I would like to, and the only other thing we have is essentially a PKI which itself stores its data, a might be FS and I pianist and so I pay gloss server.

C

Talks to these these three main components and a client give us client talk to a pig or server, and the only only data is outside of ipfs. Are these things called the follow request and that's how we implement that the social science things and we will see why they're not you know.

C

So, let's talk about the structure, so the global structure, you have a global file system and essentially you get space under your username in the global file system, and this is why we are partially why we ensure unique user names.

C

So you have everything, has a well-defined path and your file system has a tree of symmetric keys, now use tweet NaCl and we have cryptographic links between these keys in a structure called tree which I'll talk more about in a second, and so you end up with a location plus a key is cryptographic access, token or a capability, and that allows you to do something like read a file or read a directory. Alright,.

C

We explicitly done use conversion encryption, because that leads the contents of your files, and this is a diagram of the cryptic structure we use. You can see. We've got a directory on the left, a subdirectory in the middle and a file on the right. So each box is a symmetric key and each arrow is is a link from one key to another. By link I mean it's the target key encrypted with a source key.

C

So if you have one of these keys, you can follow links from that key around the diagram and drive all the keys and so yeah. So you can see a directory has two keys: a base key and a parent key. The base, key controls, access to the children of that directory and the parent key gives you access to two things.

C

But one thing really is: is the path, so it encrypts the metadata of that directory, which is its name mostly, and it also has a link to its parents parent key, so you can follow the the back links back to figure out the the path of what are we looking at files on the right?

C

We also have two keys, but don't files don't have any children so the base key there is the parent key and the other key is the data key which is used to encrypt the actual data and similarly the metadata, which has more things now. It's like file, size and mime type and so on, they're all encrypted with the parent key.

C

Now this this is the treat for controlling, read access, so if I want to just share a file with someone, as well as the location which we'll talk about later, you share this. This parent key for the file the base key similarly fro directory- and that gives you access to the entire subtree of that directory with just the one to one key and location and the corresponding structure to this or write access, looks a lot simpler.

C

So in this diagram the the red boxes- symmetric, keys like in previous one, the green ones. As you can see there, then a key pairs signing key beds. So basically every files and directories look the same from this point. This the right-click trees, point of view, so there's just one key for it.

C

For each thing, and that key has a link to or encrypts the key pair for that directory or file, and so, if someone has the base right key for a thing that means that they can then derive to keep their and that key Perry's is it's effectively. The IPS keep their, which is used to sign modifications to do two thing, and so that means that they can then modify it.

C

So we've taken the view. The right access implies read access that the trees are actually independent, but you only ever share my access with read access. Unix doesn't technically do that, but the exceptions done. Don't really apply to two files. They're more for things like a service, that's listening and you can, you can write, become read it kind of thing. So you think that makes sense.

C

So that's I'm going to talk now about what what actually happens when we're uploading the file. So we take the raw file. We split it into five megabytes chunks. Each of those five Meg chunks is independently encrypted and those are then Charlotte in 240 frames.

C

We do a few things within each file. Make chunk of like rounding it up so that you can't even introduce the size of the file modulo 5 mm so come over exactly I think we rounded up two modules at least four K, maybe more and then anyway, so during upload these these encrypted fragrancy, but those know it be first and then we have an encrypted metadata. The critter II blob with local links to these fragment hashes and each of those tree things ends up in another data structure called a champ.

C

So this is an IP LD diagram. So these links and mobile links- and you can see that you have chap nodes and then eventually you get to a crick tree node and that limb boy 2.

C

If it's a file, file, fragments and the way we've done, it is there's the serialization you can't actually from the network spotted me, you can't figure out if something is a directory or just a small file, so the serialization is identical for both, so that helps you to hide the the directory structure, even the Juke, even just the topology of a little learn the names.

C

So how does sharing work so used a public boxing key and to send a photo request? What I do is I create a directory for that friend in my space and then I send a read capability to this directory and I encrypt it to the friends public boxing team and this thing gets sent and stored on the on the friends storage server until they next login and retrieve it, and then they delete now after they processed it.

C

So what this means so that that sharing mechanism- currently that's co-chief, fi 1:9, so I mean scared, while sad files currently wonderful to a large quantum computer. If someone had but we'll move to our post quantum encryption scheme as soon as a clear canada arise, which is progressing rapidly so now the next calorie convenience.

C

So what does the login mean in a decentralized system? So we've you've explained already that pick up some capability based. So we can't stop someone from getting the ciphertext of something. What we can do is control access to keys, and so what we do is you take your password and salt it with your username and send it through a memory. Hard hashing function called script and it's tuned to take a second and that the output of that is three things.

C

We get a root symmetric, key assigning keeper, which is your identity, key pair and a boxing key pair as well, and these are only ever stored in RAM and poke cuts and no didn't a disk will transmit, so public links are basically. This is just a capability encoded in the link itself.

C

This is a fairly standard technique these days, but you have the location which has two parts to it: there's the the public writing key and there's a label and which is the lookup key in the champ and then there's the actual decryption key, and these are all put appended after the hash in a URL and so, as we know, that's not sent to the server.

C

So a public link is actually more like a secret link because the file is still on actually exposed to the network and you can share an individual file or indeed an entire folder in its century.

C

So now the next calorie security counter login, we cracked, so brute force, is practically impossible with a good password. So it's obviously only as secure as your password and we we put some work into trying to help people choose good passwords. So to the point where now we actually have a button which will generate a password for you in the browser, but so with a password that has 14 characters, alphanumeric characters about 284 possibilities or 10 or 25. So GPU can calculate about a million script hashes per second measured by litecoin users.

C

We actually use harder parameters than the light point, but it's an estimate.

C

So that means that one GPU cracking a single users login would take about 10 to the 19 seconds or 300 billion years, or if you had 300 million GPUs, it would still take a thousand years and those 300 million GPUs the costs just to buy them to learn the electricity to run them would be 300 billion u.s. dollars.

C

So you can compare that to various budgets of very consider you, your own threat model, but at the other end of the spectrum, if you drop to even I, think something like an eight character password that actually only costs something like $10,000 to crack in a year, so password length matters and what about quantum computer based attacks? So I've already mentioned that shared files currently von go to the quantum computer.

C

However, it files that aren't shared so just your own files, they are actually already safe, and the reason for this is to get from nothing to reading your files. There's only two operations, the script hashing and there's symmetric encryption, and neither of those are vulnerable to a computer. Now you get like a factor to speed up and not an exponential speed-up, so that actually phone and then the classic complaint that JavaScript crypto is insecure.

C

Now, yes, it is, but it depends on your threat model. So if we're targeting the casual user people who are happy to log into a website from someone, they trust, then that's fine.

C

They can just download the JavaScript and log in and do it for people who are who are more paranoid and maybe don't trust even DNS, then they can download the source themselves, verify it, compile it run it locally and with the power of IP first they don't need a DNS address or anything like and so yeah this we can cater to a range of threat mods. Basically, this is the idea it has to build security. We have reproducible, builds already, both server and front-end. We only have eight JavaScript dependencies, all of them bended.

C

We self host everything even fonts, there's nothing from it in third-party loaded in the web. Ui. That also helps, if you want to run it from localhost offline.

C

We have our own deterministic replacement for web pack and minifiers, and most of the client code is written in a type safe language, so Java and cross compiled to JavaScript.

C

During a time right, let's see what we can do right. It's can people see this, hopefully all right. So here we go, but this is the demo server I'm logged in now, as then, when you see, we've got a bunch of buttons here, hopefully they're mostly self-explanatory.

C

This is the social button where we can. We can add friends and sending a follow request, and so.

C

There's a bunch of different files have all the thumbnails the thumbnails are actually encrypted as part of the metadata for the files and every season. Nothing. Now, let's have a look. We can do so if we go in got some images here and you can view them in browser or download them. If you like.

C

Okay, the some images.

C

We have a very basic text viewer, so there's a recipe for lamb stew. We can also play videos. This is a more impressive demo, so this is the collage as one. So if we look at the sizes since I want to happen, 20 make so if we play that Humphry Meg would take something like a minute or so to download, but this will start playing as soon as it's downloaded the first 5 min. So you remember: the 5 make chunking thing this meet.

C

This allows us to start playing at least in Chrome, Firefox and Chrome and Safari iOS I think it works. We can stream at 5 million of time.

C

C

Bartering something okay,.

C

At least in crime we should be able to stream and play how much every large video it could be. A bigger by big chamber. You air, doesn't doesn't matter.

C

Julio I can demonstrate the the public link thing.

C

C

You right so actually think about the directory.

C

Not sure why that's there anyway, so we can create a public link to the media directory I'll, open that in a new tab you can see there's a bunch of other siblings here too the media directory. If you go to the public link, you can see the URL there. We can see the things that we've just been granted access to and if we go down a directory, then all the owners are there wicked. But if you go back up, just can't see any siblings and that's that's not just you I think.

C

That's obviously in force cryptographically.

C

Should just work as it does normally and there's a helpful sign up scene bottom.

C

So cool yep, the rest of it's fairly self-explanatory and slides right, so yeah, the other big news is on Friday. We launched our alpha for bigges. So if you want, you can sign up, there's a limited number of spots on it, but yeah alpha dot, pick us on net. Now, if you want to read some more, we have a little booklet book, stop peeing or settle or just check out our source and get on.

C

If future plans, we won't implement messaging. Our signal inside papers and an actual document editor, it's text editor and eventually a sandbox and API for third-party apps to run inside papers yeah. Any any questions.

B

Thank you very much. If you have any questions, if you could put them in a chat.

B

Sharing it'd be great.

B

C

B

Do you mind if you, let's see all right excellent? First of all, thank you very much for your presentation. That's wonderful! um Personally! I, really, like your super, clear diagrams of how you encrypted the files I think I was very useful. Thank you very much um and let us start with questions, so we don't have so much time. um Davi.

B

Do you mind picking your most pressing question and it will move on to other, so they can ask questions.

A

I'm also finding my questions instead of later every night following here goes for a while. Some of these are more like update questions, other curiosities, let's start with a vein, and then I can can pick one of my questions.

B

Alright cool, thank you. Alright, a Dean! um Oh wow! You have multiple questions as well. So I'll start with your first one. We don't mind. The first question is: have you considered using D ID based authentication schemes? How do you evoke a key so.

C

We take the view which is kind of more information theoretic view. Once someone has information, you can't take that information away from them so to to revoke it, so the keys for encryption, keys or they're all symmetric keys or there's a signing, kids against as well. Basically, you just rotate the keys. If you want to revoke access.

C

So you're just rain encrypting the data and reesh airing with anyone who wants to you want to still have access to with the new keys.

B

Awesome, okay and does anyone else want to ask a question before I get to a Dean's a Dean? Second question all right. Second question: how do users share with each other? Does this require external messaging? So.

C

It's a sharing is internal, and so once you, you can send a follower request to someone and that then gives them a read capability to a directory in your space forth, for that particular friend, and when you share a file with them. All that does is attach a capability to that file into that directory, which they already have read. Access to.

B

All right um before I go to one of these questions. I'd like to Oh Molly. You have a question well.

D

Well, I actually wanted to pick one of David's questions, because I thought it was okay.

B

D

Multiple writers, so how do you do kind of collaboration and other things like that? Incur those so.

C

Multiple writers, okay, it's whoever has has the key at the moment if it could be literally the same user on different machines because you are I, can s equivalent? Is it's basically it's your storage server. So it's not decentralized in the sense of openness.

C

When we move to openness will be a backup for in case your machine disappears, but the core thing that I think for now is still essential air service. We don't have fancy CID T's yeah.

C

We would love to do more on those lines in the long term, but for now this this works and so that what that means is that's that's just that's your centralization point for given writing space, and so, if you try to concurrently modify something, one of them will succeed in the long fail.

B

Okay, so those will be the questions for the live talk. However, this is what we're going to do if anyone else has any questions when we put up the video, if you can put up the questions in the comment section, then that will be another like alternative way for you to get your answers and in terms of next week or format, is going to be slightly different for the ipfs weekly call.

B

Oh I, see Ali's face is surprised um for the ipfs weekly call we're going to have lightning talks, so you can sign up five minutes during a call. If you have a project that you would like to present or you have something that you're working on that you want to get out there and give some feedback. This would be a perfect forum for that, and that is happening next week. Next Monday, thank you everyone and is that a hand Duffy yeah.

A

This is a good question. Is this.

B

A

You vomit or do we have a poor request.

D

On github for the new forum- yes actually purchased, it.

A

B

So I think yeah that's been merged and um we were about to do it this week, but we are going to do it next weekend spend something that's been in the works for about a month, so yeah it's there and it's merged cool. Alright, everyone I will see you next week and have a group and have a great week. Thank you. Everyone and thank you. I am think thanks.