I have large files which are broken into blocks of 512 KB and uploaded to a server. In my DB I store the IV, and the user knows the security key themselves. When downloading, I use the same IV and key.
However, is it insecure running AES-CBC on each different block with the same IV? Won't this give away information -- e.g. 1 512 block encrypted will equal the next 512 block if they are both identical? And if I can't load the entire file into memory at once, is the only safe way to do it storing many IV's? (100 GB file would have 200k IV's...)