Efficient Subversion of Symmetric Encryption with Random Initialization Vector

This paper presents an efficient subverted symmetric encryption scheme, which outputs a random initialization vector (IV). Compared with the available scheme of the same kind in the literature, our attack provides a saboteur (big brother) with much faster recovery of a key used in a victim's symmetric encryption scheme. Our result implies that care must be taken when a symmetric encryption scheme with a random IV such as randomized CBC is deployed.