Perhaps I don't understand the answers to Malleability attacks against encryption without authentication, so trying to be more concrete... please be patient. If I want to change the first block and I ...
I know that, if CBC-MAC is used in such a way that the tag is the concatenation of all the blocks' outputs (and not just the last one), it's insecure under CPA for the simplest case of 2 blocks ...
Suppose there is a message that is encrypted with AES-128-CBC. The message is as follows, new lines are used to delimit the 16 byte boundary for each block: ...