This is a follow-up for bug 1637516 comment 13 and comment 14, where first party information stored in OriginAttributes is plain-text.
The value should be hashed and salted (probably by profile id).
See Bug 1558932 comment 14. Tom has pointed out what hash we should use.
Does Fission in general have a strategy for hiding the real identifiers from the content processes?
Also, it seems that changing this would break existing users as their storage would now be keyed differently. Or would we have some migration path?
Delaying until Future, as I don't think we have concrete plans here yet, and we don't need to focus on these potential data leak issues until we have functionality completed.