 The study reports the suitability of an Einstein-Podolsky-Rosen entanglement source for Gaussian continuous variable quantum key distribution at 1,550 nanometers, which is based on a single continuous wave-squeezed vacuum mode combined with a vacuum mode at a balanced beam splitter. The security analysis shows that distances in the order of 10 kilometers are achievable with this source for a reasonable sample size despite the fact that the entanglement was generated including a vacuum mode and the security analysis applies to all states having an asymmetry in the field quadrature variances. This article was authored by Tobias Eberle, Vitus Hanschen, John Gu and others.