It seems to me that this is (albeit in a somewhat convoluted way), "solving" one problem but opening a whole can of (cryptographic) worms on another. Namely th

It seems to me that this is (albeit in a somewhat convoluted way), "solving" one problem but opening a whole can of (cryptographic) worms on another. Namely the biggest chestnut being the old classic of performing decryption on untrusted data. Since basic AES-128 is not an AEAD cipher, you are basically in the realms of trusting untrusted input. Personally my preference would be to maintain UUID (or possibly KSUID-type implementations depending on application). And then if you need to partition/shard/whatever you do that by some other means (i.e. by or in conjunction with a different database column).