A semiconductor device may include: a bus; first and second function modules configured to communicate via the bus; a first encryption module configured to encrypt first data output from the first function module using a first encryption key to generate first encrypted data; and/or a second encryption module configured to decrypt the first encrypted data using the first encryption key, to output the decrypted first data to the second function module, and to encrypt second data output from the second function module using a second encryption key to generate second encrypted data. A semiconductor device may include: a bus; first and second modules configured to communicate via the bus; and/or an encryption module configured to use different encryption policies for first data, which is output from the first module and stored in a memory, and second data, which is output from the second module and stored in the memory.