  We study the use of polar codes for both discrete and continuous variables
Quantum Key Distribution (QKD). Although very large blocks must be used to
obtain the efficiency required by quantum key distribution, and especially
continuous variables quantum key distribution, their implementation on generic
x86 CPUs is practical. Thanks to recursive decoding, they exhibit excellent
decoding speed, much higher than large, irregular Low Density Parity Check
(LDPC) codes implemented on similar hardware, and competitive with
implementations of the same codes on high-end Graphic Processing Units (GPUs).
