Re: British ISPs Block Wikipedia

On Mon, 8 Dec 2008 14:16:04 -0000, "Bazzer Smith" <me@xxxxxxxxxxx>
wrote:

You might like to look up "public key encryption" for an explanation
of how it is possible to have a 100% secure exchange of information
between 2 people, even though all the information is being seen by
someone else.

I have looked it up years ago it is obviously bull.

No, it is just *way* above your intellect.

I have just added two numbers together. The answer is 8356623418.
Could you tell me what the two numbers are?

The above is a very simple example of a one-way process. Adding two
numbers together is easy. Finding the two original numbers from the
answer is impossible.

Public key encryption does not depend on a one-way maths operation
exactly, but it depends on a maths operation that is easy to perform
in one direction but would take centuries of computing to go the other
way. There is the *possibility* that someone will discover an easier
way to perform the reverse operation (factoring a very large number),
and at that time most of our present-day encryption will become
vulnerable.

Public key encryption and decryption is extremely processor intensive,
so the entire data file is not encrypted with it. Instead, the file
is encrypted with one of many possible encryption algorithms that use
a key, the key is randomly generated as a one-off, and that key is
encrypted with the public key for subsequent decryption with the
private key at the other end.

Thus there are two places that could potentially be "cracked" One is
the public key encryption itself (which would be disasterous), and the
other is the algorithm used to encrypt the data (such as AES, DES,
Blowfish etc.)

--
Cynic

.

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