So, if LE asks who owns this allias, can they answer ?
Technically, they can.
Probably, but I don’t see the issue if you have decent opsec while buying & using the service. What will the LEOs do when they find out it directs to a proton address, and that proton address was made through Tor and payed though mixed btc? - especially when you haven’t done anything illegal.
The issue would be that one alias is tied to every alias belonging to that one Proton address (per the example) so a web of addresses would be tied together. Once subpoenas came back with all the IPs/purchases/emails received by the non-Proton side of things…a full picture is created.
Pretty sure this was asked before but could not find it immediately. But yes they can. That is the only way they can forward the emails to your inbox.
So my main inbox e-mail on my Simplelogin used to be linked to personal accounts that could eventually tie back to my real identity. Would it be enough to create a new e-mail and put it on Simplelogin (replacing the current one), or could they also disclose the prior addresses?
I guess not. I wouldnt risk that if that was my concern. I am not concerned about the swiss courts allowing this for me personally.
Remember that proton doesnt just comply with LE on their requests by default. Swiss privacy laws are stronger than yours.
Not sure what yiu use aliases for but many are linked to me in some way anyway. Those you woukd have to put in a different account then.
The way I see it, email aliasing services are mostly for preventing passive surveillance by stopping someone from linking your accounts through a single email address, not necessarily for total anonymity. However, it is good to know that once an alias is deleted, SimpleLogin says that they erase any record of who it belonged to and only keep it around to make sure it can’t be reused (source).