This influential paper led to the term Homomorphic Encryption (HE) for describing any encryption scheme where a particular operation on two ciphertext values gives an encrypted result that can be decrypted to get the result of some other operation on the plaintexts.
Since 1978, many encryption schemes have been discovered to have homomorphisms for various operations, but the question of whether any HE scheme performed both addition and multiplication operations on the plaintexts remained open for a long time.
This requires either the operations to be known in advance (at the time that the data is encrypted) or each data item has to be encrypted in multiple encryption schemes to permit multiple operations later. Unlike a single Full Homomorphic Encryption (FHE) scheme, a suite of HE schemes has restricted functionality, so some queries are not possible on encrypted data even if they are known in advance.
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