Re: Jamming IEDs

<kenney@xxxxxxxxxxxxxxxxxxx> wrote in message
> In article <1119183871.181626.259640@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
> jacklinthicum@xxxxxxxxxxxxx () wrote:
>> (The method then)nd they eventually
>> concluded that the only system that is absolutely unbreakable is one
>> with with a random, nonpeating additive key--the equation in two
>> unknowns"
> The only theoretically unbreakable cipher is a one time pad. Modern
> systems rely on the difficulty of factorising large numbers, with current
> computing. Unfortunately generating the one time pad is not easy,
> distributing them is a bitch and enforcing correct code usage is a real
> pain. The US managed to read large numbers of Soviet messages because one
> time pads were re-used.

Factorization (in the RSA algortihm) and other "trap door" algorithms
(Diffie-Hellman discrete logarithms, possibly elliptic curve systems) are
used only to facilitate key exchange, simplifying the key distribution
problem that exists for all classical cryptosystems. Key exchange has always
been a major difficulty until the advent of pulibc key systems, its just
much worse for one time pads.

Actual text encryption is done with symmetric key algorithms like 3DES. In
the pre-public key world you had to distribute the keys used via some sort
of courier network. The one-time pad allows the use of the simplest possible
encyption/decryption algorithm - the logical AND.

It seems to me that modern computer technology makes one-time pads much more
attractive for the most sensitive communications. Physical media (DVDs)
store several gigabytes, which allow encryption several gigabytes of
messages before they are used up - that is a lot of communication, 20 sets
of the Encyclopedia Britannica (text only), even more for Blu-Ray, etc.

Solid state quantum devices (like tunneling diodes) can be used to poduce
true random numbers. A special purpose chip with a large array of such
devices could produce a stream of random digits with a high bandwidth.

A special purpose computer would be used for the actual encryption and
decryption and would enforce by design true one-time use. After the DVD is
used, it is destroyed by incineration. Once this is done on both ends the
message stream becomes forever undecipherable.

Only the distribution problem remains as the major disadvantage.

Carey Sublette