Add `mprotect` to secret

[Eyob94]

Using mprotect will aid in restricting operations being done on the memory space taken by the secret. Restricted operations include but not limited to

• Read
• Write
• Execute and more

mprotect could help prevent other programs running on the same computer from operating on the secret's memory space

For more detailed info:

• https://www.man7.org/linux/man-pages/man2/mprotect.2.html