Skiff – Privacy-first end-to-end encrypted email • Hacker News Board

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

#181

Post by porridgeraisin » Thu, Aug 24, 2023, 2:04 AM UTC

m00dy wrote: post #119

amilich wrote: post #12

Earlier quoted context omitted.

Hello! Yes, we're working on this. Note that our UI, cryptography, and editor libraries are MIT licensed.

hello, how can I be sure the service mentioned above is really e2e encrypted ?

Actually I'm doing something related to this. So considering e2ee by definition doesn't require the messenger/middleman to co-operate, you can turn any communication medium into an end to end encrypted one. So I made a fully offline, client-side browser extension (it can also be a copy paste console snippet) that hooks into the send button of a POC malicious chat app and performs a key exchange for you. Then it sets up hooks to automatically encrypt messages before sending it, and also decrypt messages you receive.

So visually it looks just like you're chatting normally, but the server gets only encrypted messages.

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

#182

Post by raggi » Thu, Aug 24, 2023, 3:14 AM UTC

amilich wrote: post #150

onereplyac wrote: post #101

Earlier quoted context omitted.

Normal email proiders don't dowbload all emails whenever a user logs into a new device

We also don't do this. In a near future implementation you can just synchronize the end-to-end encrypted search index.

This step is what I was expecting you to talk about, and it has some tricky subtleties to get right, which is why I looked for it in the whitepaper.

A trivial problem with a naive implementation is being able to perform presence proofs using side channel information: send someone mail containing a terms you want to verify, and watch for the associated high level costs affecting operations that are likely to be incremental index change uploads.

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

#183

Post by amilich » Thu, Aug 24, 2023, 4:44 AM UTC

nicce wrote: post #177

amilich wrote: post #174

Earlier quoted context omitted.

Actually, that's completely false. Security audits are a standard, reputable process for software. Trail of Bits is probably the best (or one of very few top) firms in this category. Check out: https://github.com/trailofbits

Is Trail of Bits doing random checks on your running infrastucture to verify that you are not changing your software against your users? No. That is not what security audits are. Security audits ensure that software does safely what you, as service orderer claim, in a single moment. Usually including checklist. But they cannot guarantee that you don’t change software between audits. That is why E2EE exists as then it…

That's why Skiff has had 4 security audits, not just 1 3 years ago. And, with multiple of the best auditors.

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

#184

Post by Thorrez » Thu, Aug 24, 2023, 5:04 AM UTC

amilich wrote: post #74

Thorrez wrote: post #66

Earlier quoted context omitted.

What do you think of Lavabit? I think they operated in the same way, but the US government forced them out of business for refusing to hand over their TLS keys to allow the US to spy on Snowden. https://en.wikipedia.org/wiki/Lavabit

See below, Lavabit not a good comparison as it was not end-to-end encrypted. Also read https://arstechnica.com/information-technology/2013/11/op-ed...

Thanks for the information.

One similarity between Lavabit and Skiff is that tptacek calls them both non-end-to-end encrypted.

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

#185

Post by amilich » Thu, Aug 24, 2023, 5:06 AM UTC

Thorrez wrote: post #184

amilich wrote: post #74

Earlier quoted context omitted.

See below, Lavabit not a good comparison as it was not end-to-end encrypted. Also read https://arstechnica.com/information-technology/2013/11/op-ed...

Thanks for the information. One similarity between Lavabit and Skiff is that tptacek calls them both non-end-to-end encrypted.

It's very simple. One of them had access to user's private keys (Lavabit).

One never has access to user private keys (Skiff).

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

#186

Post by Thorrez » Thu, Aug 24, 2023, 5:26 AM UTC

akerl_ wrote: post #72

Thorrez wrote: post #66

Earlier quoted context omitted.

What do you think of Lavabit? I think they operated in the same way, but the US government forced them out of business for refusing to hand over their TLS keys to allow the US to spy on Snowden. https://en.wikipedia.org/wiki/Lavabit

Lavabit is the one that used user passwords to encrypt the messages, thus ensuring that they had access to all the necessary secrets to decrypt user messages any time the user was viewing them? And that had complied previously with US government subpoenas to provide metadata and data for users?

>And that had complied previously with US government subpoenas to provide metadata and data for users?

Interesting. Link? Are you talking about this article? https://www.forbes.com/sites/kashmirhill/2013/08/09/lavabits...

It seems to be talking about metadata, not data.

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

#187

Post by tptacek » Thu, Aug 24, 2023, 5:40 AM UTC

amilich wrote: post #185

Thorrez wrote: post #184

Earlier quoted context omitted.

Thanks for the information. One similarity between Lavabit and Skiff is that tptacek calls them both non-end-to-end encrypted.

It's very simple. One of them had access to user's private keys (Lavabit). One never has access to user private keys (Skiff).

I don't understand how you don't have exactly the same access they did. I feel like I've invested a fair bit of time to understanding how this stuff works, and the story you're telling doesn't make sense. What am I missing?

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

#188

Post by tptacek » Thu, Aug 24, 2023, 5:42 AM UTC

amilich wrote: post #175

tptacek wrote: post #172

Earlier quoted context omitted.

You haven't published the reports, scope, and full findings. We don't even know what Trail was testing. I don't think the security audit stuff matters at all, and Trail is a fine firm, but you can't use the mere existence of a pentest project this way.

Any security engineer would have a heart attack if any employee, friend, or colleague said "security audit stuff [doesn't] matter." I wouldn't use software that doesn't undergo security audits. Also, pentest ≠ audit. Completely different!

I am a security engineer. You can go reach out to whoever managed your assessment at Trail and ask them about me by name if you like. What you're saying doesn't make sense. Maybe you could make it make sense! But you'd need to start by disclosing what the actual project scopes for each of these projects was.

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

#189

Post by tptacek » Thu, Aug 24, 2023, 5:43 AM UTC

amilich wrote: post #183

nicce wrote: post #177

Earlier quoted context omitted.

Is Trail of Bits doing random checks on your running infrastucture to verify that you are not changing your software against your users? No. That is not what security audits are. Security audits ensure that software does safely what you, as service orderer claim, in a single moment. Usually including checklist. But they cannot guarantee that you don’t change software between audits. That is why E2EE exists as then it…

That's why Skiff has had 4 security audits, not just 1 3 years ago. And, with multiple of the best auditors.

What exactly got tested in each of these assessments, and what conclusions did those assessments draw? I asked this upthread and I'm asking here again, because "we've had 4 audits" doesn't mean anything without that detail.

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

#190

Post by onereplyac2 » Thu, Aug 24, 2023, 6:06 AM UTC

tptacek wrote: post #187

amilich wrote: post #185

Earlier quoted context omitted.

It's very simple. One of them had access to user's private keys (Lavabit). One never has access to user private keys (Skiff).

I don't understand how you don't have exactly the same access they did. I feel like I've invested a fair bit of time to understanding how this stuff works, and the story you're telling doesn't make sense. What am I missing?

What amilich said is correct. However, what he is leaving out is that both have access to unencrypted email at send and recieve time, so you are taking Skiffs word that they dont log emails - since you have to trust the server this is not e2ee.