# Tag Info

The important thing to note here is that $\mathsf{D}(k,0)=0$ does not necessarily imply that $\mathsf{E}(k,0)=0$. That is the reason why your attack does not work in general. To illustrate, let $(\mathsf{E},\mathsf{D})$ be a CCA secure encryption scheme. We then construct a new encryption scheme $(\mathsf{E'},\mathsf{D'})$ as follows: \mathsf{E'}(k,m) = ...