  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.
