
Mozilla’s Send makes it easy to send a file from one person to another - Tomte
https://www.theverge.com/2017/8/2/16086272/mozilla-send-file-sharing-service-launches
======
pmlnr
Remember why we were able to use Skype for this? _Pepperidge farm remembers!_

Joke aside I transfered a lot of files inside instant messengers and they
worked quite well. Nearly everyone had at least a yahoo/messenger/skype/icq
account, which made this rather simple, and, because nobody had the
capacity/wasn't insterested/was actually p2p, it was perfectly fine. A bummer
if the modem connection went down or you had to hang up because the family
wanted to make a call, but hey, it was glorious. (no, this is not sarcasm, it
really did work.)

~~~
Kpourdeilami
Apple mail has this really cool feature that when you email someone a file
that is too large, it uploads it to Icloud automatically and then sends that a
person a downloadable link from Icloud that expires in 30 days

~~~
pmlnr
Thunderbird has/had this as well, you could even select a few providers, like
Box and that Ubuntu cloud which is now deprecated. Probably a decent solution,
but still needs a 3rd party server, which you didn't with the p2p im
solutions.

~~~
vanous
I use it regularly and have self hosted webdav server for this reason. iirc,
extension for custom server is required, but the functionality comes from
Firefox.

------
nneonneo
Neat. It uses client-side crypto (AES-128-GCM) to secure the file; the key is
in the fragment portion of the URL so it doesn't automatically hit the server
(assuming you trust the server JS).

The protocol is a little bit strange, though. The file metadata is transmitted
as an X-File-Metadata header on upload, and includes the SHA256 hash of the
original (unencrypted) file (as the "aad" parameter to the X-File-Metadata
upload parameter). This is a little concerning for privacy; while the filename
is easy to disguise, hiding the SHA256 sum requires modifying the file in some
way. Of course, this might only be a concern for uploading known files, but
it's still a bit of an infoleak.

It's also strange in that the key isn't checked in any way (even for sanity)
before initiating a download, so if you mess up and leave it off (or corrupt
some bits), you won't find out until the _end_ of the download that you can't
get the file. Worse, the file will be deleted, forcing you to ask your sender
for another copy.

The client-side crypto has one other downside: there doesn't seem to be a
standard way in JavaScript to stream a POST request yet. You could emulate it
with e.g. WebSockets, but those are a lot more heavyweight and CPU-intensive
(for the server) than simple POST requests. So, the current implementation
just encrypts the entire file as one giant block, and then uploads it -
placing the whole file in memory. Hence the 1GB soft-limit. Downloads are
similarly limited.

Luckily, non-browser clients can do whatever they like, so I wrote a Python
client that's compatible with the server, but uses streaming POST and on-the-
fly en/decryption to save memory. Check it out at
[https://github.com/nneonneo/ffsend](https://github.com/nneonneo/ffsend) \-
feedback welcome!

~~~
bastawhiz
> This is a little concerning for privacy; while the filename is easy to
> disguise, hiding the SHA256 sum requires modifying the file in some way. Of
> course, this might only be a concern for uploading known files, but it's
> still a bit of an infoleak.

Does it matter? The file is behind a URL with a random id (and the hash
expires from redis after a day). Even if someone guessed your id within a day,
they know essentially nothing about your file or you. And if they had your
URL, they could download the file anyway, making it moot.

> Hence the 1GB soft-limit.

Mozilla stores the files on S3. That needs a reasonable limit.

~~~
nneonneo
Mozilla, on the other hand, knows your SHA-256 and your IP. So if you're
uploading some known offensive file, the logs could be subpoenaed, etc. etc.
Normally it's just preferable to have the service provider know as little as
possible.

------
supercanuck
It is kind of surreal that it is 2017 and we're still trying to solve such a
basic computing problem.

~~~
epicide
I don't think it's a computing problem as much as it is a UI problem.

We can send the shit out of some files... if you know what you're doing
(browsers retrieve tons of files all the time, for example).

It's difficult creating a service that is accessible to people who barely
understand what a file is in the first place.

~~~
simias
IMO the main problem is the mainstream use of NATs and the fact that most
people don't run their computers 24/7\. The internet became the internat.

If all computers were publicly reachable it would be trivial to send files
peer-to-peer.

I guess IPFS can be an interesting solution to this problem.

~~~
wongarsu
With the advent of smartphones, most people are running a computer 24/7\. But
that computer is still either behind a NAT or on a connection where data is
precious.

NAT punching is a thing, but it makes the implementation of p2p a lot more
complicated.

~~~
seanp2k2
UPnP was supposed to help with this as well before it became a security
disaster. There's also stuff like
[https://github.com/danoctavian/bluntly/blob/master/README.md](https://github.com/danoctavian/bluntly/blob/master/README.md)
to do NAT holepunching without a central server (using DHT) but again adoption
and the actual ergonomics of usage (npm, the config file, key distribution etc
make it fail the "could my grandma use it" test) are not easy enough to make
it easy enough for the un-devops'd masses.

------
falcolas
This is a bummer; using Safari:

Your browser is not supported. Unfortunately this browser does not support the
web technology that powers Firefox Send. You’ll need to try another browser.
We recommend Firefox!

It would be nice to know what web tech they are using that isn't supported.
Whatever it is, Chrome works.

EDIT: It requires support for the AES-GCM key type, with a size of 128.

~~~
sp332
From user eridius a couple days ago: "It's checking for window.crypto.subtle.
Looks like Safari TP supports this. I believe the problem with Safari 10 is
that it implemented an older version of the web cryptography standard."
[https://news.ycombinator.com/item?id=14904307](https://news.ycombinator.com/item?id=14904307)

~~~
falcolas
Well, it looks like Safari (and edge) do support it, but not the AES-GCM key
type.

[https://developer.mozilla.org/en-
US/docs/Web/API/SubtleCrypt...](https://developer.mozilla.org/en-
US/docs/Web/API/SubtleCrypto/generateKey)

I'll leave it up to someone wiser than me to indicate if this is the proper
choice. AES-GCM key type with a length of 128.

~~~
aaomidi
AES-GCM is great tbh. Authenticated encryption built into one.

------
dec0dedab0de
Otherwise technically illiterate people used to be able to do this with AIM
direct connect over 15 years ago. It still blows my mind that AOL had a near
monopoly in this space, and lost it by continually making the user experience
worse.

~~~
empath75
Aim was a potential multibillion dollar business that AOL just threw away. It
was facebook before facebook existed.

~~~
mac01021
How would they have earned those billions of dollars?

~~~
nl
Same way FB does now.

The idea of FB status updates (and Twitter) literally came from the status
line you could set in AIM.

------
mih
I always wonder how Opera Unite (in 12.x) versions would have fared had it
gained traction. The sender had absolute control over what files were shared
and how long they could be without needing to rely on a 3rd party to host
content or setting up a complex service on localhost. Opera did kill it off
the Unite service even before they migrated to Webkit/Blink, but it is
something I remember fondly.

~~~
fzzzy
That sounds amazing. I really hope we see this in another browser some day.

I wrote the original TCPSocket implementation for Firefox OS. As I was doing
it I imagined an architecture like what you described. I know at least some
prototype apps which worked in a similar way were developed.

------
false-mirror
I really hope Mozilla decides to expand on this.

One issue with the experiment is it has such a narrow use case. Disappearing
after one download / 24hrs makes sending a file to multiple people--or just
one person who drags their feet on the DL-- makes it really inconvenient to
use. Even offering "1 download -OR- 24hrs" would make it far more useful.

~~~
Spivak
But at that point it's just a file hosting platform. Why not use a public
Drive/Dropbox/OwnCloud/Mega/S3 link?

~~~
problems
Client-side encryption. Mega works, may use some questionable cryptography,
but the rest of your solutions don't offer that at all.

------
dmart
Hmm... it seems like most of the time when I want to transfer a large file to
someone (or to another one of my own devices), I just want to do it
immediately and only once, so there's no need to upload it to a third,
temporary location.

Unfortunately it seems like most of the time a physical USB flash drive is the
most efficient way to accomplish this. Seems absurd to me that in 2017 there's
not a common, user-friendly way to just establish a direct connection between
two web browsers and directly push files through.

~~~
pmlnr
> _between two web browsers_

They were never inteded to be active senders or p2p workers. I know, we've
come a long way in the past 2 decades, but I never expected this to be the job
of the browser. I'm also aware of webRTC and I'm a bit uncertain why that
can't be used to send/receive files.

~~~
r1ch
There are a bunch of WebRTC file transfer web apps but they unfortunately all
suffer from the legacy cruft that WebRTC brought along. The only data channels
are UDP and things like STUN / TURN / ICE are needed to have any hope of
breaking through NAT, often with disappointing results.

~~~
filiwickers
Ya, for Dat[1], we had a WebRTC implementation and it was unreliable compared
to our other clients. We are hoping other in browser p2p options get
developed, e.g. [https://github.com/noffle/web-
udp](https://github.com/noffle/web-udp).

[1] [https://datproject.org](https://datproject.org)

------
amq
A really needed service, but I doubt it will last for long, because it's far
from the core business and because it will potentially cost more than Mozilla
is willing to dedicate.

~~~
qqg3
WeTransfer has been around a long time and is exactly the same.

------
Sjenk
I did a quick scan of the article but is there any difference with wetranfser?
The only things I found is encryption and it is 1gb less. But since Wetransfer
is a dutch company they are not allowed by law to look in those files you send
if I am correct.

~~~
Markoff
i think wetransfer doesn't automatically delete files within 24 hours or one
download

this Mozilla service seem really useless over tons of others like mega.nz, is
it really that big deal to delete file manually?

~~~
qqg3
WeTransfer does auto delete after 7 days I believe and on the plus plan you
can do things like password protect links.

------
vit05
I really don't get why people are criticizing and saying that there are better
alternatives to this. Of course there is. This was not built to be the best
way to send files, just to be the most practical one. Some people don't even
know there is life outside of Facebook, they will never know about
alternatives to send a file they could not send using email or messager. And
this shows that Mozilla is starting building services layers on Firefox.

------
JD557
From the repo, it appears that it depends on S3.

It would be nice to be able to self-host this on a small home server for
friends and family. That way, even if they shut down their server, you could
still share files with your friends.

~~~
6a68
The code's on github, so you could definitely just stand up your own copy:
[https://github.com/mozilla/send](https://github.com/mozilla/send)

------
Sir_Cmpwn
A better approach in 2017 is something like File Pizza:
[https://file.pizza/](https://file.pizza/)

This uses WebRTC to transfer files peer-to-peer.

~~~
dijit
YES, this is what I was hoping send was, another implementation of webrtc p2p
file sharing.

Unfortunately it is not.

My only issue with filepizza is, I wanted to host one internally, but it has a
hard dependency on a hardcoded list of torrent trackers. (I have a DENY ALL
firewall rule at the border which can't be touched) :(

~~~
Sir_Cmpwn
There are other things with a similar concept. The core JS behind this is a
couple hundred lines at the worst.

~~~
dijit
ideas on where to look?

I really prefer p2p if available, and on my LAN it doesn't have to traverse
NAT or anything.

~~~
filiwickers
Check out Dat:
[https://datproject.org/install](https://datproject.org/install).

We do NAT traversal but also connect to local peers over multicast DNS.
Command line client should have a local or offline option to restrict only to
local peers soon.

~~~
Sir_Cmpwn
Where's the code?

~~~
filiwickers
[http://github.com/datproject](http://github.com/datproject). It is pretty
modular so if you need help finding something hop in our chat:
[http://chat.datproject.org](http://chat.datproject.org).

=)

~~~
Sir_Cmpwn
Thanks!

------
redm
I find "burn after reading" downloads for a number of reasons, but generally,
they often don't work as intended.

For example, modern email services (Google, MS, etc.) accessing links in
emails and download the content and check it for malware. They probably
mitigated this but its caveats like this that cause messages to be burned
before the intended reading.

~~~
sterex
True! Also like one commenter said on the original article, if I have to share
a file with 3 users, I will have to upload it 3 times and also there's the
case of failed downloads.

Not sure if this is viable.

~~~
saimiam
Why are jumping from imagining a specific use case (1:N file share) failing
(with little evidence that the product doesn't/can never recover from failures
seamlessly) to calling into question the entire product?

Give the product a chance, imho.

------
merpnderp
How is Mozilla going to keep this viable? Since they're using S3, it likely
costs them roughly $.08/GB moved between users in bandwidth costs plus
whatever fraction of a month the file is left there of the $.025 GB/month
storage costs.

~~~
Sylos
Personally, I don't think that they'll keep it. It is specifically in the Test
Pilot program which is for trying out and seeing the response for things, even
if they are not necessarily realistically going to be put into the browser.

~~~
wongarsu
But if there were no plans to expand it if successful, what would be the point
of the experiment in the first place?

~~~
devrandomguy
Perhaps to asses its value to users, before building the production version?
S3 is a quick and simple solution.

------
option_greek
They need to make the url human memorable. Something like
/files/what/a/nice/day. This seems to be aimed more for sending over emails.

~~~
coldtea
Nobody (for most values of "nobody") communicates downloads urls over the
phone. So, yes, this is for sharing over emails, chat, etc.

The url is not memorable on purpose: it's a uuid so people can't just guess it
and access other's file.

~~~
option_greek
It need not be communicated over the phone. Say you want to move a file from
desktop to your mobile. Or transfer quickly from your iOS phone to your
friends Android one. This will help in those cases but is limited by the
randomly generated url which you will have to pain stackingly type. I don't
see how a sufficiently long randomly generated string with memorable words
(/jack/never/securely/farted/sky/fall/what/ever) is less secure than randomly
generated token like this.

~~~
nileshtrivedi
Why will you have to type the URL? You just send the URL to the person over
any communication medium. For your own devices, you even have apps that
provide shared clipboard so you just copy on first device and paste on
another.

~~~
Pxtl
Not OP, but I've occaisionally found that it's very hard to send messages
between my own machines, because most platforms are based on users - not
machines.

I can message my wife from my phone to her phone, but I can't message myself
from my phone to my PC. At least, with most messaging programs.

~~~
wongarsu
One of the advantages of telegram: it's trivial to message yourself. Really
handy for sharing links or just as a notepad

------
rythie
It's a nice idea, though I'd really like to just run one myself (inside the
firewall), seems like that would be safer, at least in the eyes of users.

~~~
sdiepend
[https://github.com/mozilla/send](https://github.com/mozilla/send)

------
deanclatworthy
Surely this is going to be incredibly expensive in the long-run for Mozilla? I
can't quite get what their play is with this service.

~~~
wongarsu
I suspect they have plans to make this into some form of browser feature, if
it's successful and they make good experiences. It is a task people normally
use websites for, and in the past that was enough justification for Mozilla to
turn something into a browser feature.

------
amelius
This will also be solved by IPFS, [1].

[1] [https://ipfs.io/](https://ipfs.io/)

~~~
talklittle
How is expiration of files achieved with IPFS? I thought files stored on IPFS
were available forever.

If my impression was correct, then Firefox Send supports different use cases
than IPFS.

------
LinuxBender
My personal preference are browser agnostic methods[1] and giving the sender
the choice to use whatever method of encryption they wish. I prefer the
simplicity of 7-zip / p7zip, but others may prefer PGP.

[1] [https://tinyvpn.org/](https://tinyvpn.org/)

------
varunramesh
I use [https://transfer.sh/](https://transfer.sh/) for this kind of ephemeral
file transfer. They have drag/drop through website, integration with ShareX,
and even an alias that you can add to your shell.

------
emcf
Firefox Send How to use guide [https://medium.com/@pushpendradevsharms/how-to-
use-firefox-s...](https://medium.com/@pushpendradevsharms/how-to-use-firefox-
send-a-simple-guide-2eb288ebc7d8)

------
booleanbetrayal
`brew install magic-wormhole`

~~~
guessmyname
You are assuming that everyone on HackerNews has a Mac.

Here is a link with installation instructions for every major platform.

— [https://github.com/warner/magic-wormhole](https://github.com/warner/magic-
wormhole)

------
kwelstr
Does anybody remember IRC's DCC send?

~~~
dijit
DCC Send is an excellent solution (although quite crappy UX until you get used
to it). It does, however, suffer from a couple of limitations which make it
inviable in 2017.

1) It can't traverse NAT, you have to forward the ports on your router- which
is quite frustrating.

2) It can't use ipv6, which would have eliminated the first problem, but
unfortunately without ipv6 it can't do that.

Unless of course you have a dedicated IPv4 for your DCC sender and receiver,
but I think that is improbable.

------
darkstar999
Can this link be changed away from clickbait Verge? Perhaps
[https://github.com/mozilla/send](https://github.com/mozilla/send)

~~~
mintplant
In what way is this article "clickbait"?

~~~
Sir_Cmpwn
Blogspam would be a more accurate term.

------
pwaivers
Relevant XKCD: [https://xkcd.com/949/](https://xkcd.com/949/)

~~~
pmlnr
Yesterday I wanted to quickly send over some large files from my debian server
to an ancient windows one on my home network. The server is running on ZFS, so
in theory, install samba, set usershares on, zfs set smbshare=on rpool/x.

I ended up copying over on an SD card after ~1 hour of fighting with smb
version compatibility, smb vs linux permissions, workgroup mismatches due to
localised windows.

~~~
icebraining
I find HTTP generally much more reliable. Normally I use woof (just run "woof
<file>" to start an HTTP server serving that file), but I'd like to find
something better, since it doesn't handle multiple connections well.

woof also supports uploads (shows a basic uploading page), which is nice when
you want to transfer to a server.

[http://www.home.unix-ag.org/simon/woof.html](http://www.home.unix-
ag.org/simon/woof.html) (but it's packaged in Debian)

~~~
fzzzy
I do this all the time too. I use Twisted wherever twistd is installed by
default:

    
    
      twistd -n web -p 8000 --path ./path/
    

I've also used the npm package http-server when node is more convenient:

    
    
      npm install -g http-server && http-server -p 8000 ./path/

~~~
nileshtrivedi

      python -m http.server

------
mtgx
Is this using WebRTC?

Either way looks like a good promotion trick for Firefox if many people end-up
using. Good job whoever came up with it and convinced Mozilla leadership to
deploy it.

------
masthead
Firefox is getting it right these days! From Container tabs to Snooze Tabs to
Firefox send to Quick notes from the browser. This is all I wanted!

------
iuguy
Does anyone else find it ridiculous that a platform supposedly committed to
open standards releases something that doesn't even work cross-browser?

For a cross-browser, self-hosted tried and tested alternative, there's 0bin:
[https://github.com/sametmax/0bin](https://github.com/sametmax/0bin)

------
locusofself
Bittorrent "Sync" was a promising application until they tried to monetize it
and made it worse (Resilio Sync).

~~~
aoeusnth1
How is it worse? Asking for a friend.

~~~
locusofself
When it first came out, it "just worked". The simplicity of the folder=key was
great. If you have the long key passphrase, you are in.

Then they implemented a whole bunch of features that I thought were clunky,
emailing the passphrase, QR codes I think, the ability to require approval to
access shares, sub-permissions, etc.

2 years ago or so they released a version that was not backward compatible, so
everyone had to upgrade or not, and if only some peers had upgraded, things
got out of "sync" heh.

Finally, we got my team all on resilio sync and we all had 100% CPU pegs on
certain shared folders.

I gave up on it.

When it was really simply and it synced it was great

------
nstart
Surprised no one mentioned file.io. They've been around for a while with the
exact same use case + an API.

------
Abishek_Muthian
If this picks up, email services (who own cloud sharing facilities) might put
up a huge warning in red stating the security risk for their users in clicking
that link. I wonder whether Mozilla feels having the file scanned by
virustotal before encrypting violate user privacy.

~~~
floatingatoll
If you can compile virustotal to a .js file so it runs client side, I'm sure
they'd be open to considering a pull request / bug implementing that =)

------
izzydata
So what is this going to cost the user in the future? I can't imagine this
will be a free service forever if Mozilla has nothing to gain from eating up
tons of bandwidth.

~~~
floatingatoll
At $10 per TB of network data transfer, with the guarantee of a single inbound
and outbound copy of the data file, it's more likely that some jerk will try
to DDoS the service to make themselves feel puissant than it is that this will
cost a significant amount of money as a TestPilot experiment.

------
millzlane
I prefer [https://send-anywhere.com/](https://send-anywhere.com/) they have a
4GB limit.

------
edgartaor
Some times I use volafile.org. Keep your files for two days. Although it's not
suitable for private files it's easy to use.

------
hobbes78
I still believe instant.io is better, as it's P2P and uses bittorrent
underneath (actually, a web version of it)...

------
martinald
Is this not exactly the same as WeTransfer?

~~~
mintplant
This is open source and encrypts your files so that Mozilla can't read them.

~~~
martinald
TBH for most people that use WeTransfer I don't think this is a major concern,
though it maybe should be.

This smacks of Mozilla misjudging the market again and wasting a lot of time
and money on things that just won't work at scale. Annoying because they are
by far the richest 'tech charity' and have a lot of really amazing engineers.
More Rust and Servo (concepts that very few people can execute on), less
random startup ideas, I think.

~~~
mintplant
> This smacks of Mozilla misjudging the market again and wasting a lot of time
> and money on things that just won't work at scale.

It's an experiment, part of the Test Pilot program. A relatively low-budget
MVP to test the waters and see if the concept is worth exploring. If not, the
experiment ends and the organization moves on.

The program exists precisely to counter your concerns here while ensuring
Mozilla can continue to innovate in new areas.

------
amelius
Does this allow one to send a file to an iPhone, and let the user store it
somewhere, and view/play it?

------
akilism
Onionshare....

[https://onionshare.org/](https://onionshare.org/)

------
praveenkrs
This was the best feature I like about the google talk desktop client. And was
sorry to see it leave.

------
ucho
Makes me wonder when Firefox will be able to resume interrupted file downloads
without addons.

------
caffinatedmonk
I built DnD, a self hosted file transfer program. It's like scp with a UI.
Check it out on github:
[https://github.com/0xcaff/dnd](https://github.com/0xcaff/dnd)

------
cdnsteve
Is there an API developers can use to leverage this?

~~~
JulienSchmidt
Open an issue on the repo and suggest it!

I assume it is a bit difficult though, since the encryption is performed in
the browser. Thus API clients had to perform the exact same crypto to use this
service.

------
emcf
Firefox Send is great service. Thank Firefox

------
digitalengineer
www.wetranfer.com : just upload add email and send. They even have OSX
intergration. (Up to 2 gb free)

------
longqzh
Can we access it from China?

~~~
yorwba
I just tried it and looks like the GFW doesn't block it yet. Upload speed was
surprisingly good too, much better than I ever get downloading foreign
websites.

------
albertgoeswoof
Well no, it's nothing like snapchat, what kind of title is this

Great that Mozilla are experimenting but this article literally adds nothing
to the original Mozilla blog post and website and has no value whatsoever

~~~
unpwn
Well the fact that it disappears after the first download makes it similar to
what snapchat originally was

~~~
albertgoeswoof
Good point. BUT, comparing it to snapchat implies a tonne of other things that
this isn't (potential for millions of users, teenage users targeted, super
cool interface that no one can use except teenagers, ...). This is a clickbait
title and shouldn't be encouraged

------
dingo_bat
Looks like a web implementation of Samsung link sharing. Cool. Hope to use it
often.

------
altern8
Why, though.

------
snakeanus
I don't really see the point. We have had temperately file hosting services
for years. Moreover I find the fact that it requires JS and multiple 3rd party
resources in order to work properly extremely annoying (all the other services
that I know of do not require that).

I think that it would be better if Mozilla focused more on their important
projects, such as Firefox, Servo and Rust.

~~~
ape4
Doing a quick google, the other temporary file hosting services have much
smaller limits. Firefox has a better reputation than these others (for
confidentiality, etc)

~~~
snakeanus
I found these two temporary file hosting services that have similar or bigger
limits (1GB was the one that Mozilla had, right?):

[https://dropfile.to/](https://dropfile.to/) \- 1GB (requires js, not third
party however. It also has a nice API)

[https://lewd.se/](https://lewd.se/) \- 5GB

That being said, there are many more permanent file hosting services which one
can use instead.

~~~
ape4
lol, I probably wouldn't use lewd.se for business ;)

------
whowouldathunk
Seems superfluous. In Windows 10 you can right click on a file > Share >
choose any app or person to send the file. Or in the latest version you can
just drag/drop a file on top of a person pinned to your taskbar.

Disclosure: I work at Microsoft.

~~~
goldfire
The only items I have in that sharing menu are e-mail, which clearly there
would be no need for this service if that were good enough, OneNote, which
makes no sense, and advertisements for Store apps that I don't want to use. I
think it's safe enough to say that menu does not replace a service like this.

~~~
whowouldathunk
The problem with that is Windows' lack of apps. The UX is better and will be
consistent regardless of if you're sharing from an app, File Explorer, or file
picker.

Mozilla's service could just plug into it.

------
brianberns
> Mozilla says it “does not have the ability to access the content of your
> encrypted file.”

This can't possibly be true. Since Mozilla is encrypting the file, they can
also decrypt it (and must do so when the recipient downloads it).

Edit: I was wrong, but will leave this comment because the explanation is
useful.

~~~
ericmoritz
I don't know for certain without digging into the code but they are probably
using the WebCryptoAPI and doing everything client-side to encrypt the file.

The URL that is shared contains the key for the file. You'll notice that the
URL contains a fragment identifier, i.e the #foo part of
[http://example.com/#foo](http://example.com/#foo), this isn't transmitted to
the server by the browser and therefore the key isn't exposed beyond who the
URL is shared to.

[https://www.w3.org/TR/WebCryptoAPI/](https://www.w3.org/TR/WebCryptoAPI/)

~~~
criddell
Doesn't it come down to us trusting Mozilla though?

~~~
dragonwriter
Yes, since they could change the JS without notice from to do something
different, and could conceivably be ordered by a government to do so generally
or targeting a specific set of users.

------
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