摘要 |
A multi-functional system includes a main system, and sub-systems operated by sub-programs and the main system. The sub-systems includes a first memory storing a first public key, and a second memory storing an encrypted sub-program and second public key, a first communication controller transmitting the first public key for encrypted communication, a decryption unit decrypting the encrypted sub-program and second public key using an encryption key, and a second controller transmitting the decrypted second public key for encrypted communication. The main system includes a first public key, a second public key, a security device, and first and second communication controllers. The sub-systems execute a plurality of corresponding subprograms under the control of the main system.
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