@MojtabaRafiee Sorry, I don't have any bright ideas. It doesn't seem likely to be feasible if this is a many-time MAC rather than a one-time MAC—that the equation relating F_k(m1), F_k(m2), t1, and t2 is a sum of products of them suggests to me that this won't work.

@MojtabaRafiee If you need someone's attention on an exotic novel primitive like this, you are probably better off hiring a cryptographer than asking pseudonymous strangers on the internet.

@SqueamishOssifrage Thanks for helping you.

@SqueamishOssifrage gasp! That can't be, that string is clearly uncompressable and therefore must have maximum entropy!!1!

You guys have a really odd definition of /dev/random. It's not the same definition as Theodore Ts'o's definition, which is a paperclip with googly eyes hot-glued to it. Whatever. Let's just agree to disagree.