If an attacker has a full data dump, they probably have a recent/frequent queries dump too. Column name obfuscation won't go very far. Zipcodes are short. If n

If an attacker has a full data dump, they probably have a recent/frequent queries dump too. Column name obfuscation won't go very far. Zipcodes are short. If not given extra padding, their ciphertexts will still be short. Zipcodes are also low cardinality. Unless you use multiple salts/nonces/IVs/keys, the frequency of ciphertexts will match the frequency of plaintexts. In many situations, a prepared attacker will be able to insert their own data beforehand, allowing them to perform a chosen-plaintext attack and potentially decipher much of the data. The best protection against this is to not reuse salts/nonces/IVs/keys and thus again defeat performant searches. None of this is to necessarily say it's not worth it but rather to keep in mind the article's point: know your threat model.