  We describe an encrypted communication principle that can form a perfectly
secure link between two parties without electronically saving either of their
keys. Instead, cryptographic key bits are kept safe within the unique
mesoscopic randomness of two volumetric scattering materials. We demonstrate
how a shared set of patterned optical probes can generate 10 gigabits of
statistically verified randomness between a pair of unique 2 cubic millimeter
scattering objects. This shared randomness is used to facilitate
information-theoretically secure communication following a modified one-time
pad protocol. Benefits of volumetric physical storage over electronic memory
include the inability to probe, duplicate or selectively reset any random bits
without fundamentally altering the entire key space. Beyond the demonstrated
communication scheme, our ability to securely couple the randomness contained
within two unique physical objects may help strengthen the hardware for a large
class of cryptographic protocols, which is currently a critically weak link in
the security pipeline of our increasingly mobile communication culture.
