That would work after the user has been targeted, but not on any emails they received before that (if the system I suggest could be implemented). What I'm imaging is not perfect, but perhaps better than nothing.
What's the alternative exactly? Getting an email service in a country that can't legally force this on someone?
How to prevent email phishing attacks - a quick guide 2019-11-29 / First published: 2017-05-18 https://tutanota.com/blog/posts/how-to-prevent-phishing/
Transparency Report & Warrant Canary for the secure email service Tutanota 2016-01-01 / Updated: 2020-01-17 https://tutanota.com/blog/posts/transparency-report/
Secure email service Tutanota is being blocked by AT&T in parts of the United States February 13, 2020 https://www.grahamcluley.com/tutanota-email-blocked/ Tutanota: AT&T is blocking Tutanota. This shows why we must fight for net neutrality.
That sucks of course, but the simple solution is a quality VPN. Sure lets keep screaming at them, but in the meantime I want access to my Tutanota as needed.
Russian govn blocked Tutanota service in Russia to stop encrypted communication February 17, 2020 https://securityaffairs.co/wordpress/98002/laws-and-regulations/russia-blocked-tutanota.html Tutanota: Tutanota is blocked in Russia in an attempt to stop encrypted communication
Results of the first ever Tutanota poll We have asked your opinion about the encrypted email service Tutanota April 7, 2020 https://tutanota.com/blog/posts/tutanota-encrypted-email-poll
Naturally, the alternative would be to use PGP/GPG to set it up in an E2EE manner yourself. But, obviously, this would mean that your contacts are required to do the same. Another option would be to host your own mailserver - which in turn requires skills and effort to set it up and keep it running smooth and secure.
another site comparing privacy focused email providers, bashing Proton and Tuta among the others while recommending Riseup, Disroot, Posteo, Autistici. https://digdeeper.neocities.org/ghost/email.html
Update on the recent DDoS attack on Tutanota This weekend a sophisticated DDoS attack was launched against Tutanota August 18, 2020 https://tutanota.com/blog/posts/update-ddos-attack
I love Tutanota. Flawless performance on my end. Hopefully they can prevent further DDOS much more quickly. Luckily for me I wasn't using their service during the past critical time.
Continuous DDoS is an attack on our right to privacy Tutanota keeps being attacked - now we must fight for our right to privacy September 7, 2020 https://tutanota.com/blog/posts/ddos-attack-tutanota
I suspect the 3letters. Stupid of them not to ask for ransom. Like I've said dozens of times if you have top notch anonymity & advertise it. Then you are sure to be attacked until they have a way in that is not detected. That's why (& I'm lazy) I don't learn how to have nation-state security. Besides my info is already available to them. But I could be wrong.
Transparency Report & Warrant Canary for the secure email service Tutanota 2016-01-01 / Updated: 2020-09-09 https://tutanota.com/blog/posts/transparency-report/
DDoS attack on our DNS infrastructure Multiple DNS providers were attacked to take down Tutanota September 17, 2020 https://tutanota.com/blog/posts/ddos-dns-attack
German secure email provider Tutanota forced to monitor an account, after regional court ruling December 8, 2020 https://techcrunch.com/2020/12/08/g...nitor-an-account-after-regional-court-ruling/
Fixed vulnerability in Tutanota March 25, 2021 https://tutanota.com/blog/posts/security-review-fixed-vulnerability
Tutanota desktop clients end beta phase June 21, 2021 https://tutanota.com/blog/posts/desktop-clients-end-beta
via email (February 26, 2022) "Subject: Changes of Terms": Previous Terms and Conditions (via archive.org) https://web.archive.org/web/20220129101300/https://tutanota.com/terms/
Be advised that Tutanota has a 'handholding' clause in their TOS, that requires one to log in within a certain period of time (every 3 months? 6 months?), and failing to do so means they will shut down your account, and good luck trying to contact them to challenge it, or ask for refund. While this is clearly stated in their TOS for free accounts, it is not so stated for paid accounts....yet I can attest to the fact it is exactly the same. Tutanota shut my paid account down a good three months before the next bill was due, for lack of activity. Lack of activity does not mean no one was sending mail, it means I was only checking mail once or twice a year. If you are thinking about getting a Tutanota account, my advice is to stick with the free one. The only difference between it and the paid one is they can rip you off with the latter. And read the TOS carefully...very carefully.