Re: Customised Extra Entanglement in Vector Cryptography.



On Sat, 22 Oct 2011 16:47:03 -0700 (PDT), adacrypt
<austin.obyrne@xxxxxxxxxxx> wrote:

Asking for two files of plaintext as he did on top of being inside the
database is laughable. He would make a worse thief than he is as a
cryptanalyst.
You really need to read some history. The attacker can *always* find
some plaintext/cyphertext pairs. It is so common that there is even a
name for this sort of attack: the "known plaintext attack". If your
cypher cannot withstand a known plaintext attack then it is too weak
to be of any use.

Now some history. The day before the Pearl Harbour attack, Tokyo sent
a long cyphertext to its embassy in Washington. The next day the
Japanese Ambassador handed a long plaintext statement to the US
Government. A perfect plaintext/cyphertext pair.

The fact that the US had already broken the Japanese code is
irrelevant; the attacker can *always* find a plaintext/cyphertext
pair. If your cypher cannot withstand a known plaintext attack, then
it is weaker than AES, which has been tested against such attacks.

rossum

.