[Cryptography] "Perpetual Encryption"

[Allen]

On Wed, Mar 29, 2017 at 1:19 PM, Mark Steward <marksteward at gmail.com> wrote:
> On Wed, Mar 29, 2017 at 5:12 PM, Bill Cox <waywardgeek at gmail.com> wrote:
>>
>> It is not possible to increase the entropy of a remote machine when an
>> eavesdropper is listening.  The remote machine requires its own TRNG, or
>> some ability to collect unpredictable events not seen by the eavesdropper.
>
> Unpredictable data that's sent over a secure channel is still
> unpredictable. Or are you saying it's difficult to set up a secure
> channel without good entropy?

An interesting corollary it seems to me (which is probably not new,
but is new to me), is that if you encode a message containing Em bits
of "entropy" using a key that has Ek bits of "entropy", and then
transmit it across a public channel, the resulting message has Ek bits
of "entropy", not Em bits of entropy, since the Em bits of entropy are
revealed to to the world when the message is transmitted and all that
is left is the Ek bits of entropy in the key.  This would also
indicate that one of the key claims in the perpetual encryption
whitepaper--that the entropy is increased by mixing with the random
data and therefore the scheme 2^X times stronger than any other
encryption scheme--is incorrect because the entropy remaining in the
transmitted message cannot be greater than the entropy of the key or
initial secret PRNG state needed to decrypt the message.