TPM is a dedicated microcontroller used to secure computer systems by integrating cryptographic keys and encryption/decryption processing into hardware. Generally, pushing the security down to the hardware level provides more protection than a software-only solution. This problem is eliminated if the keys used in TPM are not accessible on a bus or to external programs and all encryption/decryption is done in TPM.
At boot TPM runs an authentication check on your hardware, software, and firmware. If the TPM detects an unauthorized change, your computer will boot to a restricted mode to deter potential attackers.