i don't think so. the attack is extracting a single byte. so without any random iv you will get one of 256 values spread across whatever the block size is. t

i don't think so. the attack is extracting a single byte. so without any random iv you will get one of 256 values spread across whatever the block size is. that size doesn't matter - you still have just 256 values to test for. your argument only applies if the rest of the data are appended to the plaintext. [disclaimer: i'm no cryptographer, just using simple logic here]