Effective Privacy Amplification for Secure Classical Communications
The authors explain the practical effectiveness of privacy amplification for classical key-distribution schemes. They find that in contrast to quantum key distribution schemes, the high fidelity of the raw key generated in classical systems allow the users to always sift a secure shorter key if they have an upper bound on the eavesdropper probability to correctly guess the exchanged key-bits. The number of privacy amplification iterations needed to achieve information leak of 10x8 in existing classical communicators is 2 or 3 resulting in a corresponding slowdown 4 to 8. They analyze the inherent tradeoff between the number of iterations and the security of the raw key.