Re: Confirmation of Shannon's Mistake about Perfect Secrecy of One-time-pad

On Nov 6, 11:08 pm, wangyong <hell...@xxxxxxx> wrote:
how you can compute, how can you find the probability M not changed.
do not just the the result ,that is useless.

Compute the joint probability of M, K and C
(use the known probability distribtuions of M and K
the fact that M and K are independent, and the formula
for getting C from M and K)

Assume C fixed. Two cases.

For each case note the value of C and compute
the conditional probability of M using the known
joint probability of M, K and C and the definition
of conditional probability.

In both cases you get the same probability
distribution for M

- William Hughes >
- -

a change in form but not in content,you just use the probability when
c is not fixed.


No. I do not use the probability when
c is not fixed. I compute the conditional probability. This
can be computed from the joint probability, but
is not the same as the unconditional probability
(the probability when c is not fixed).

- William Hughes

.

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