Final answer:
The last step of the site-to-site IPSec encryption process is decrypting the encrypted data at the destination site.
Step-by-step explanation:
The last step of the site-to-site IPSec encryption process is decrypting the encrypted data at the destination site. During the site-to-site IPSec encryption process, the data is first encapsulated and encrypted. Then, it is sent over the network using IP packets with the encrypted payload. Once it reaches the destination site, the encrypted data is decrypted using the appropriate keys, allowing the original data to be retrieved and processed.