Patent ID: 7831050

Claim:
A cryptographic system for key distribution comprising: at least one emitter unit comprising: a source that provides a signal; a physical random generator that provides a sequence of random bits; and a modulator that modulates the signal from the source in accordance with the sequence of random bits from the physical random generator and a starting secret key that is shared with a receiver unit to provide a ciphered signal that is transmitted from the emitter unit to the receiver unit, wherein the modulator modifies the signal from the source into elliptically polarized light states; and at least one receiver unit that receives the ciphered signal, the receiver unit comprising: a demodulator that demodulates a received ciphered signal in accordance with the shared starting secret key to provide outputs representing the sequence of random bits, wherein the receiver unit utilizes the sequence of random bits obtained from the received ciphered signal as a next cipher key to be used.