  We study efficient quantum certification algorithms for quantum state set and
unitary quantum channel. We present an algorithm that uses
$O(\varepsilon^{-4}\ln |\mathcal{P}|)$ copies of an unknown state to
distinguish whether the unknown state is contained in or $\varepsilon$-far from
a finite set $\mathcal{P}$ of known states with respect to the trace distance.
This algorithm is more sample-efficient in some settings. Previous study showed
that one can distinguish whether an unknown unitary $U$ is equal to or
$\varepsilon$-far from a known or unknown unitary $V$ in fixed dimension with
$O(\varepsilon^{-2})$ uses of the unitary, in which the Choi state is used and
thus an ancilla system is needed. We give an algorithm that distinguishes the
two cases with $O(\varepsilon^{-1})$ uses of the unitary, using much fewer or
no ancilla compared with previous results.
