Unconditional security at a low cost

By simulating four quantum key distribution (QKD) experiments and analyzing one decoy-state QKD experiment, we compare two data postprocessing schemes based on security against individual attack by L\"utkenhaus, and unconditional security analysis by Gottesman-Lo-L\"utkenhaus-Preskill. Our results show that these two schemes yield close performances. In QKD, since unconditional security is highly sought after, we conclude that one is better off considering unconditional security, rather than restricting to individual attacks.