Email Security for Every Taste
Email Security for Every Taste
As someone who has read plenty of discussions about email security (some of them in this very community), including all kind of stuff (from the company groupie to tinfoil-hat conspiracy theories), I have decided to put too many hours some time to discuss the different threat models for email setups, including the basic most people have, the "secure email provider" one (e.g., Protonmail) and the "I use arch PGP manually BTW".
Jokes aside, I hope that it provides an overview comprehensive and - I don't want to say objective, but at least rational - enough so that everyone can draw their own conclusion, while also showing how certain "radical" arguments that I have seen in the past are relatively shortsighted.
The tl;dr is that email is generally not a great solution when talking about security. Depending on your risk profile, using a secure email provider may be the best compromise between realistic security and usability, while if you really have serious security needs, you probably shouldn't use emails, but if you do then a custom setup is your best choice.
Cheers
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Nice post. My two cents:
- Can you make the images clickable? They're impossible to read at that size.
- This paragraph should probably mention that this won't work if the provider uses E2EE: "Using secure email providers means that a lot of trust is placed into the provider itself. A failure or a breach of the provider can result in the content of your emails being disclosed, which means you should choose a provider you trust, ideally with a good track record and some formal certifications that attest at least basic security. However, the attacks that are specific to this setup are complex and expensive. Unless you are a high profile target, it's very unlikely they will ever be relevant to you."
Thanks!
Can you make the images clickable? They’re impossible to read at that size.
I will look into it, there might be a zola option for it. If there is, sure!
This paragraph should probably mention that this won’t work if the provider uses E2EE
That paragraph is in the context of what I call "transparent encryption", which means E2EE works until the provider is not compromised and the E2EE is effectively broken by delivering malicious software or disclosing the key. E2EE is as resilient as the security of the provider, which is why picking a trusted one is important. Of course, compromising the provider and breaking the E2EE is quite complex.
I suppose, but is there any documented occurrence of that? It seems like a whole stack of what-if scenarios required for that to happen. At that point you should be more concerned with someone beating your password out of you.
Not that I know, which is the reason why I essentially didn't consider those threats relevant for my personal threat model. However, it's also possible it happened and it was never discovered. The point is that there are risks associated with having the same provider having access to both the emails (and the operations around them) and the keys/crypto operations.
The cost of stealthily compromising a secure email company is simply disproportionate compared to the gain from accessing my emails. Likewise, it's unrealistic to think some sophisticated attacker would target me specifically to the point that they will discover and then compromise the specific tooling I am using to access/encrypt/decrypt emails. Also, a $5 wrench could probably achieve the same goal in a quicker and cheaper way.
If I were a Snowden-level person, I would probably consider that though, as it's possible that the US government would try to coerce -say- Proton in serving bad JS code to user X. For most people I argue these are theoretical attacks that do not pose concrete risk.