I`m reading the PDF "The Galois/Counter Mode of Operation (GCM)". In section 4.1 on the optimization of multiplications with tab, in algorithm 3 I have the following questions:
- A vector called M with 128 bits is created, then the value of H is copied into that vector, now M  is the same as H, is not it? Or is it after those 128 bits? In programming would be that way.
If I believe that the 128-bit vector is created, and these remain null. because if not the while cycle does not make sense. in this the value of i is multiplied by 2 this results in 128, and the principle of H would be multiplied with the plain text?
- P in the plain text, but no matter how long this is, only the first 128 bits of the plain text will be multiplied with H?
Later, it is stored in the vector, but it is being overwritten by what I see in the division of i / 2?