During an encryption process, a database system may generate an index value based on the plaintext to be encrypted, an encryption key, a data field-specific salt, or a combination thereof. The database may store the index value in an index associated with the ciphertext output of the encryption process. In some cases, the database may receive a query specifying a plaintext value for filtering on a data field, where the database may return data objects with the specified plaintext value in the given data field. The database may compute a set of index values associated with the specified plaintext, and may identify indexes with index values included in the set of index values and associated with the given data field. The database may decrypt the ciphertexts associated with the identified indexes to check if they match the specified plaintext.