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Skiff – Privacy-first end-to-end encrypted email

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Re: Skiff – Privacy-first end-to-end encrypted email

#51

Post by ignoramous »

bastawhiz wrote: post #34
tptacek wrote: post #29

Earlier quoted context omitted.

Section 8.2 seems to talk about how you send plaintext email via SMTP to users who aren't using Skiff. But that's not what I'm talking about with respect to end-to-end encryption. The white paper refers repeatedly to "browser" users. Your server can feed arbitrary Javascript to browsers and subvert encryption in a variety of ways, can't it? I'm still not clear why you designed a new, simplistic cryptosystem at all he…

> Your server can feed arbitrary Javascript to browsers and subvert encryption in a variety of ways, can't it? That's how literally any website works. How do you encrypt in the browser if the server doesn't send JavaScript to encrypt data? You also trust Signal not to issue an update that sends data in plaintext over the network. Unless you're building an app from source, you implicitly trust the developer to some ex…

> How do you encrypt in the browser if the server doesn't send JavaScript to encrypt data?

Meta has done some work along with Cloudflare on this for WhatsApp Web, specifically. In general, JS crypto is always going to be suspect if the threat model involves distrusting the server (like in e2ee protocols like Signal).

Re: Skiff – Privacy-first end-to-end encrypted email

#52

Post by raggi »

raggi wrote: post #50
amilich wrote: post #45

Earlier quoted context omitted.

Done completely client side. We actually have multiple blogs on this - https://skiff.com/blog/private-search

So if I have 15gb of email, I have to process all of that on every client bootstrap? How do you plan on scaling your service with respect to this problem? once you have a non-trivial user base with non-trivial data volumes this is likely to become a substantial problem.

To put this in context, the trivial example of a user with a 15gb account, say you happened to be using s3 for storage. They buy a new phone, that costs you ~$1.50 that month, or 50% of your revenue at current pricing. They buy a new iPad and a new laptop? You’re 50% in the red.

Similarly you’ll have some users who are, say, content creators. They shove a 10gb video in their drive. Let’s say they have a laptop, a workstation, a phone and an iPad. Their upload is downloaded at least 3 times, costing you ~$4.50.

Re: Skiff – Privacy-first end-to-end encrypted email

#53

Post by mgraczyk »

wishywashy0 wrote: post #27
tptacek wrote: post #21

From the white paper, it appears as if this system requires its users to trust the server. That's not end-to-end encryption. What do I have wrong here? Further, it looks like the email encryption provided by this system only works between users of Skiff. At that point, why use email at all? Why not use a real secure messenger? Instead of building an "encrypted email service", you could literally just build an email-f…

Founding engineer at Skiff here. >From the white paper, it appears as if this system requires its users to trust the server. That's not end-to-end encryption. What do I have wrong here? It doesn't. All data is encrypted client side across all apps - Skiff Mail, Drive, Pages, and Calendar. For sending external, the whitepaper is very clear how this case is handled in section 8.2 as securely as possible (without having…

Worth noting that Google does not do what you're describing. Google has never literally "sold" data from Gmail and stopped using it for their own ads ~6 years ago.

Re: Skiff – Privacy-first end-to-end encrypted email

#54

Post by tptacek »

dannyobrien wrote: post #46
raggi wrote: post #37

Earlier quoted context omitted.

Signal doesn’t have a web client. Most of the stores it is distributed through have fairly strong resistance to compel orders.

Yep, but Signal is still a potential adversary, and could roll out a backdoor. A couple of things that are easier in a web-delivered tool is deliver a backdoor to a user or group of users (which Skiff can track), or deliver a backdoor over a particular window of time across many users to decrease the chance of detection. I know Skiff uses IPFS in some of parts of their solutions, and there's something they could do w…

Signal's servers can't backdoor the Signal Client. From what I understand of Skiff, Skiff's servers are the client.

Re: Skiff – Privacy-first end-to-end encrypted email

#55

Post by tptacek »

amilich wrote: post #48
tptacek wrote: post #29

Earlier quoted context omitted.

Section 8.2 seems to talk about how you send plaintext email via SMTP to users who aren't using Skiff. But that's not what I'm talking about with respect to end-to-end encryption. The white paper refers repeatedly to "browser" users. Your server can feed arbitrary Javascript to browsers and subvert encryption in a variety of ways, can't it? I'm still not clear why you designed a new, simplistic cryptosystem at all he…

It would be far more illogical to warp Matrix into an end-to-end encrypted calendar, note-taking product, file storage product, and email platform.

Why? You'd use Matrix to distribute keys for encrypted blobs. That's how systems like these work anyways.

Re: Skiff – Privacy-first end-to-end encrypted email

#56

Post by mlhpdx »

raggi wrote: post #52
raggi wrote: post #50

Earlier quoted context omitted.

So if I have 15gb of email, I have to process all of that on every client bootstrap? How do you plan on scaling your service with respect to this problem? once you have a non-trivial user base with non-trivial data volumes this is likely to become a substantial problem.

To put this in context, the trivial example of a user with a 15gb account, say you happened to be using s3 for storage. They buy a new phone, that costs you ~$1.50 that month, or 50% of your revenue at current pricing. They buy a new iPad and a new laptop? You’re 50% in the red. Similarly you’ll have some users who are, say, content creators. They shove a 10gb video in their drive. Let’s say they have a laptop, a wor…

Yeah, this is where it gets real. VC funding and unbounded potential operational costs. Ouch.

Re: Skiff – Privacy-first end-to-end encrypted email

#57

Post by ginsbergjason »

mgraczyk wrote: post #53
wishywashy0 wrote: post #27

Earlier quoted context omitted.

Founding engineer at Skiff here. >From the white paper, it appears as if this system requires its users to trust the server. That's not end-to-end encryption. What do I have wrong here? It doesn't. All data is encrypted client side across all apps - Skiff Mail, Drive, Pages, and Calendar. For sending external, the whitepaper is very clear how this case is handled in section 8.2 as securely as possible (without having…

Worth noting that Google does not do what you're describing. Google has never literally "sold" data from Gmail and stopped using it for their own ads ~6 years ago.

So gmail was making money off of personal emails as recently 2017. Why trust them? There is no good reason they shouldn’t e2ee that data.

Re: Skiff – Privacy-first end-to-end encrypted email

#58

Post by ignoramous »

redeux wrote: post #4

The pricing page is confusing to me. It doesn’t mention anything about email in the free tier. It just says: > Unlimited pages > Desktop, tablet, and mobile access > IPFS support > Full text search Which seems to be all about the document service, but it also doesn’t mention how much storage I get. I assume it’s not unlimited despite saying “Unlimited pages.” Also, I can see that Skiff has raised over $14M in VC fund…

> Skiff has raised over $14M in VC funds, so as a privacy-focused product...

They seemed to have pivoted from web3? https://news.ycombinator.com/item?id=29797691

Re: Skiff – Privacy-first end-to-end encrypted email

#59

Post by Sytten »

The data is still located in the US so honestly for email I would not see the benefit since so much of it will pass through unencrypted on a cloud provider (AWS?).

I personally use mailfence with IMAP on Thunderbird (so its not full E2E encryption despite the marketing) but I much prefer the Belgian privacy law.

Though the mobile/destop apps looks very nice and overall kudos for what seems like a coherent ecosystem (something I miss from my patching of sync.com and mailfence). Also concerned by VC money in that space, hopefully you are profitable. Nobody wants to have to move their life (calendar, drive, emails) because they trusted a startup that ran out of money...

Re: Skiff – Privacy-first end-to-end encrypted email

#60

Post by ignoramous »

tptacek wrote: post #21

From the white paper, it appears as if this system requires its users to trust the server. That's not end-to-end encryption. What do I have wrong here? Further, it looks like the email encryption provided by this system only works between users of Skiff. At that point, why use email at all? Why not use a real secure messenger? Instead of building an "encrypted email service", you could literally just build an email-f…

> That's not end-to-end encryption. What do I have wrong here?

Apparently, email may not their main e2ee usecase. The CEO at Skiff wrote this on PrivacyGuides forums:

  Our solution for external sharing was not intended for email. It is much more powerful to share E2EE real-time collaborative docs/files with subpages, embedded E2EE files, and so much more.
Curiously, in the same thread, there's is a mention of Trail of Bits auditing their codebase twice.

https://discuss.privacyguides.net/t/skiff-mail-email-provide...

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