When making an IV for AES-256 CBC mode the IV should be random and shouldn't be able to be guessed.
If I were to use the
rand() function in C, seeded with
time(NULL) to generate sim random numbers which would then be put through sha256, would that be a secure IV or would that still be vulnerable as the seed was the time?
I am under the impression that the IV is only there so that the same data encrypted twice with the same key would come out differently because of the IV.