[Cryptography] "Perpetual Encryption"

[Bill Frantz]

On 3/28/17 at 1:50 PM, patrick at rayservers.net (Patrick Chkoreff) wrote:

>I wonder, is this some variant of the idea of starting with a shared
>unpredictable one-time pad K1, and sending the encrypted message (xor K1
>M1) along with (xor K1 K2), where K2 is a new unpredictable one-time pad
>to use for the next encryption?

OK. With this scheme you can calculate message 2 (M2) encoded 
with K1 by: M2 xor (K1 xor K2). Now if you have any known 
plaintext in message 1 (M1) you can decode the same offset in M2.

I knew there was a reason I was ignoring the source material for 
this thread.

Cheers - Bill

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