Or instead of billions it could be one. A “rainbow” table may be needed to crack every possible hash, but a “just this very specific shade of orange” table is needed to crack one hash.
Like your abusive ex had an email address for you, buys access to a database with customer information that is “secured” by hashing email addresses, hashes your email address, finds it in the table, and gets enough information to figure out where you are living now.
When you think about security of private information, it has to work if a potential attacker is looking for a specific person that they already have some information about.
