  Privacy amplification (PA) is the art of distilling a highly secret key from
a partially secure string by public discussion. It is a vital procedure in
quantum key distribution (QKD) to produce a theoretically unconditional secure
key. The throughput of PA has become a bottleneck of the high-speed discrete
variable QKD (DV-QKD) system. In this paper, a high-speed modular arithmetic
hash PA scheme with GNU multiple precision (GMP) arithmetic library is
presented. This scheme is implemented on two different central processing unit
(CPU) platforms. The experimental results demon-strate that the throughput of
this scheme achieves 260Mbps on the block size of 10^6 and 140Mbps on the block
size of 10^8. This is the highest-speed recorded PA scheme on CPU platform to
the author's knowledge.
