  We use a rectangular pulse to freeze the possibility of estimating the
coherent parameters ($\theta,\phi$) of a single qubit and the encoded
information. It is shown that, as the possibility of estimating the parameters
increases, the amount of encoded information decreases. The pulse strength and
the detuning between the qubit and the pulse have a different effect on the
estimation degree and the encoded information. We show that if the weight
parameter, $\theta$ is estimated, the encoded information depends on the
initial state settings. Meanwhile, the encoded information doesn't depend on
the estimated phase parameter,$\phi$. These results may be useful in the
context of quantum cryptography, teleportation and secure communication.
