I considered hashing GDPR data previously in a project, and found that "one-way" hashing didn't really exist in our use case. If the number of possible inputs

I considered hashing GDPR data previously in a project, and found that "one-way" hashing didn't really exist in our use case. If the number of possible inputs is small enough, you can just rehash them all, and then your "one-way" hash becomes two-way.