Interesting new cipher patent

[Eugene Leitl]

A question: assuming, you have a class of random number generators with
lots of internal state. (Lots: like >>10^6 bits). Let's say the evolution
through state space of that generator is provably reversible (or nearly
reversible), and that the Hamiltonian of the system is stochastic (system
evolution is a randomwalk in state space). The result is a pseudorandom
number generator with a ridiculously long periode, and good randomness of
output, obviously. A simple cypher based on it would exchange the
pseudorandom generator state (the key) through a secure channel,
similiarly to a one time pad.

Can someone point me towards papers describing construction of above
generators? I'm thinking about reversible cellular automata (is Gutowitz
the only guy who did CA crypto?) or automata networks with changing
connection geometry (i.e. the connection is also encoded in the state and
changes with each iteration) with the number of total iterations estimated
from lightcone considerations.

Point of this:

* algorithmic construction of PRNGs with provable properties
* lots of internal state, hence bit leakage even for a lot of messages
  buys attacker little
* scalable (add more state as hardware improves)
* directly mappable to hardware, very good parallelism

Any pointers?


On Wed, 27 Feb 2002, Khoder bin Hakkin wrote:

> Cipher mixer with random number generator
>
>                                                        Abstract
>
> An encryption device has a random number generator whose output is
> combined by exclusive-or with plaintext input which has been encrypted
> by a first block cipher. The combined exclusive-or output is encrypted
> with a second block cipher mechanism which produces a second enciphered
> output. The output of the random number generator is also encrypted by a
> third block cipher mechanism which produces a third enciphered output.
> The first and second block cipher mechanisms differ from each other.
>
> United States Patent
> 6,351,539
> February 26, 2002
>

-- Eugen* Leitl <a href="http://leitl.org">leitl</a>
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