-3
votes
0answers
82 views

Why is the basic (fixed-length) CBC MAC construction not a secure MAC when it is used on variable-sized messages? [closed]

Why is the basic (fi xed-length) CBC MAC construction not a secure MAC when it is used on variable-sized messages?
3
votes
1answer
143 views

CBC-MAC , fixed length, all blocks returned

CBC-MAC, with fixed length message. Is it safe to return all ciphered blocks instead of the last? My intuition says it is less secure, since is gives an attacker more information. But how could one ...
2
votes
2answers
234 views

Modifications of CBC-MAC

I'm preparing myself to exam, but I have a lot of troubles with rigorous proofs. This post is very long, but this is because I remind here 2 long definitions. At the beginning I want to remind the ...