Secure sharing of random bits over the Internet

TL;DR

This paper introduces a practical scheme for securely sharing random keys over the Internet using physical noise and optical sources, enabling absolute security without relying on computational assumptions.

Contribution

The work presents a novel method combining physical noise and optical random sources to securely renew shared keys over arbitrary Internet channels, independent of computational difficulty.

Findings

Secure key renewal over the Internet is feasible with physical noise.

The scheme provides absolute security without third-party trust.

Information-theoretic bounds for security are quantitatively established.

Abstract

Although one-time pad encrypted files can be sent through Internet channels, the need for renewing shared secret keys have made this method unpractical. This work presents a scheme to turn practical the fast sharing of random keys over arbitrary Internet channels. Starting with a shared secret key sequence of length K_0 the users end up with a secure new sequence K >> K_0. Using these sequences for posteriori message encryption the legitimate users have absolute security control without the need for third parties. Additionally, the security level does not depend on the unproven difficulty of factoring numbers in primes. In the proposed scheme a fast optical random source generates random bits and noise for key renewals. The transmitted signals are recorded signals that carries both the random binary signals to be exchanged and physical noise that cannot be eliminated by the attacker. These signals allow amplification over the Internet network without degrading security. The proposed system is also secure against a-posteriori known-plaintext attack on the key. Information-theoretic analysis is presented and bounds for secure operation are quantitatively determined.