I read the summary of deniable encryption on wikipedia:
https://en.wikipedia.org/wiki/Deniable_encryption
Then I read a question, by doom123
on security.SE:
https://security.stackexchange.com/questions/34684/truly-deniable-encryption
But I had a subtly different problem which can be stated as follows:
- Alice wants to send Bob the book "Mocking Jay" which is banned in Bob's country.
- Alice encrypts "Mocking Jay" to data
MJ
with the passwordP1
. - Using another book of similar size (or by trimming a larger book), say the "The Hobbit", she processes the data
MJ
and computes passwordP2
.
The solution to this problem will allow Bob to claim that he maintains a copy of "The Hobbit" (assuming that "The Hobbit" is not banned of course), while being able to read "Mocking Jay". The solution, in theory, should also allow Bob to plausibly deny that there's any other copy hidden in the data "MJ" other than "The Hobbit"; or like the aforementioned security.SE question, should allow "MJ" to hold any number of copies (and thus any number of passwords), providing Bob the excuse of acknowledging only one copy that he has the knowledge of.
The answer provided by the user lynks
to the question posed by doom123
solves the problem for storing data on a hard-disk. Is there a general solution to this problem?
UPDATE 1
With regards to the answer provided by fgrieu
I am slightly modifying the question. Is it possible to add a third layer (and an arbitrary number of further layers) of such encryption? What I mean is, with Mocking Jay
, The Hobbit
, and Silmarillion
(assuming that the books are roughly the same in size) as inputs, is it possible to create an encrypted output say MJTHSI
? I am alright with the passwords being the output as well. Decrypting with password P1
will reveal Mocking Jay
. If rubber-hose is used password P2
can also be given up revealing The Hobbit
(with the intention of ultimately protecting Silmarillion
which can be revealed using P3
).