High-Throughput AES Transciphering using CKKS: Less than 1ms

Fully Homomorphic encryption (FHE) allows computation without decryption, but often suffers from a ciphertext expansion ratio and overhead. On the other hand, AES is a widely adopted symmetric block cipher known for its efficiency and compact ciphertext size. However, its symmetric nature prevents direct computation on encrypted data. Homomorphic transciphering bridges these two approaches by enabling computation on AES-encrypted data using FHE-encrypted AES keys, thereby combining the compactness of AES with the flexibility of FHE.