  The no-masking theorem for quantum information proves that it is impossible
to encode an input state into a larger bipartite entangled state such that full
information is stored in the correlation, but the individual subsystems have no
information about the input state. Here, we ask the question: Is it possible to
mask an observable such that the information about the observable is available
in the joint system, but individual subsystems reveal nothing about the
imprints of observable? This generalises the notion of no-masking theorem to
quantum observables. We prove that for qubit systems, an arbitrary observable
cannot be masked. Subsequently, we generalise the no-masking theorem for
observables in higher dimensions. We also prove a no-hiding theorem for
observables which goes beyond the conservation laws under symmetry operations.
Furthermore, we prove that the famous unconditional no bit-commitment result
follows from the no-masking theorem for observbles. Our results can have
important applications in quantum information and quantum communication where
we encode information not in states but in observables.
