In a fully homomorphic message authenticator, Alice can authenticate some large data $D$ using her secret key $s$k. She chooses a label $\tau$ for it, and the authentication algorithm authenticates the data $D$ with respect to the label $\tau$.
But, how and where are these labels stored?
Syntax
part of the article. You send $\sigma$ as the authenticator of the bit and after eval, Verify uses the bit $e$, program $P$ and the tag of the evaluation $\psi$ $\endgroup$ – kelalaka Nov 19 '19 at 12:06