Someone can tell me what is the use of const unsigned char *?

Question

I'm learning and I wanna now how use const unsigned char * and const char*

Answer 1

unsigned - it cannot have negative values
const - constant, you cannot change its value after assigning
* - pointer

Answer 2

const char* is useful for pointer to a string that will not change. ie your program will print some string, like the same welcome messages every time it starts.
The unsigned version is useful for pointer to a binary sequence you may want to write too a file.