Re: multi-key encryption algorithm is meaningful?

chaeso writes:

> of course, both plaintexts are reasonable.
> That's why I made this simple encryption scheme.
> but this scheme looks not secure even I cannot find attack and looks
> inefficient.
> Is this scheme publishable to domestic conference? Is this scheme is
> completely invaluable?
>
> I'm fool undergraduate school student. Please let me know

I'm not sure if any complex cryptosystems exist that can produce a
single ciphertext that will decrypt to either of two plaintexts based
on the decryption key.

An example of a system that _will_ do this is the one-time pad. You
can encrypt any plaintext with a random key, then XOR the ciphertext
with a second plaintext to obtain a second key. The first key is used
to obtain your original plaintext; the second can be used to decrypt
the very same ciphertext to a completely different plaintext of your
choice.

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