| CPC H04L 63/0428 (2013.01) [H04L 9/0866 (2013.01); H04L 9/0891 (2013.01)] | 6 Claims |
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1. An electronic device comprising:
a communicator communicating with a plurality of external devices each generating an encryption key;
a memory; and
a processor,
wherein the processor stores a plurality of encrypted messages in the memory when receiving the plurality of encrypted messages each encrypted with the encryption key by the plurality of external devices through the communicator,
performs a key switching operation using a switching key for the plurality of encrypted messages to change each of the plurality of encrypted messages to the encrypted message encrypted with a common key,
evaluates the changed plurality of encrypted messages by using at least one evaluation key, and
controls the communicator to transmit an evaluation result to at least one of the plurality of external devices,
wherein the processor receives an individual switching key, an individual relinearization key, and an individual rotation key, generated by each of the plurality of external devices through the communicator, and adds the respective individual switching keys, individual relinearization keys, and individual rotation keys to acquire the switching key, a relinearization key, and a rotation key, and
the at least one evaluation key includes the relinearization key or the rotation key.
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