  The random switching of measurement bases is commonly assumed to be a
necessary step of quantum key distribution protocols. In this paper we show
that switching is not required for coherent state continuous variable quantum
key distribution. We show this via the no-switching protocol which results in
higher information rates and a simpler experimental setup. We propose an
optimal eavesdropping attack against this protocol, for individual Gaussian
attacks, and we investigate and compare the no-switching protocol applied to
the original BB84 scheme.
