Implementation for message recovery from image

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@gmail.com>
Added reveal_message reveal logic

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@gmail.com>
Add validation functions and complete reveal_message functionality

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@gmail.com>