A customer replaceable unit monitor (CRUM) integrated circuit (IC) includes: a secure module configured to receive an encryption key and an encrypted test code from outside; and a CRUM module controlled by the secure module. The secure module may perform authorization on the basis of the received encryption key. The secure module may perform decryption of the encrypted test code to generate a decrypted test code. The secure module may store the decrypted test code in a volatile memory. The secure module may generate a test command based on the decrypted test code in the volatile memory, and provide the test command to the CRUM module.