  Estimation of channel parameters is important for extending the range and
increasing the key rate of continuous variable quantum key distribution
protocols. We propose a new estimator for the channel noise parameter based on
the method of moments. The method of moments finds an estimator from the
moments of the output distribution of the protocol. This estimator has the
advantage of being able to use all of the states shared between Alice and Bob.
Other estimators are limited to a smaller publicly revealed subset of the
states. The proposed estimator has a lower variance for high loss channel than
what has previously been proposed. We show that the method of moments estimator
increases the key rate by up to an order of magnitude at the maximum
transmission of the protocol.
