Add canonical e-mail blocks for suspended accounts

[Gargron]

Prevent new accounts from being created using the same underlying e-mail as a suspended account using extensions and period permutations. Stores e-mails as a SHA256 hash

[ClearlyClaire]

ok, if this is bound to an actual account, maybe we don't need to hash the address?

[Gargron]

Meh, I like the hash. Maybe it will replace keeping the user record on suspended accounts in perpetuity.

[anghenfil]

Hey,
doesn't this feature lead to blocked "firstnamelastname" when someone with "firstname.lastname" get's blocked and therefore leads to overblocking similar email addresses?

[nightpool]

@anghenfil Many email providers, such as gmail, do not distinguish between firstname.lastname and firstnamelastname—emails for both addresses go to the same inbox. This change prevents attackers from using such email providers to evade blocks

[anghenfil]

@nightpool yes, some/many, but not all. Personally I only know this behaviour from gmail. I think it's not a good idea to risk overblocking.

[nightpool]

You're free to remove the restriction on your own server.

[DC7IA]

Wow, did you know you can have a second email address? :D

[anghenfil]

If someone tries to get a new mastodon account they could just use a temporary email address or a new email address. I don't think using canonical email blocks will result in fewer new accounts from a banned person. It will just affect innocent people since especially big email provider have many really similar email addresses. I don't think "You're free to remove the restriction on your own server." helps, since new users mostly don't choose their instance based on an instance setting ...

Best
anghenfil