Re: Key entropy, stream entropy, block entropy, block population entropy AKA uniique stream length

On 2007-02-10, jt64@xxxxxxxx <jt64@xxxxxxxx> wrote:
On 10 Feb, 12:33, clark <c...@xxxxxxxxxxx> wrote:
I'll try this again...

On 6 Feb 2007 12:28:49 -0800, j...@xxxxxxxx wrote:

<snip discordant stuff>

Well ok now i had it *PLEASE RUN MY CIPHER* with a one byte key or two
byte password/key and you will notice one thing about the stream *IT
HAS SAME ENTROPY THAT A 256 BYTE KEY*

So you are saying (and doing a lot of hand-waving and shouting) that
using a one byte password/key gives the same entropy as using a 256
byte password/key.

No i never said a that the a ONE byte key has same entropy as a 256
byte key.
I said that a *STREAM* generated from a ONE byte key have same
properties and entropy as a *STREAM* generated from a 256 byte key.

Given a truely random 1 byte key and a truely random 256 byte key,
that is patently wrong.

The *STREAM* generated from the 1 byte key, regardless of how long it
is, will have a MAXIMUM of 1 byte of entropy.

The *STREAM* generated from the 256 byte key, regardless of how long
it is, will have a MAXIMUM of 256 bytes of entropy.

To understand this, you need to know what entropy IS, which you have
not yet shown you do.

Thus the algorithm will not now the *ORIGINAL* length of key, because
it is expanded into a 256 byte block "THAT IS KEYDEPENDENT" and there
is no trouble doing this since 256! is a lot bigger 2^256 or 2^8
whateever keylength you chose that is smaller than 256!.

There is absolutely no problem in extending the key as long as you
want. You could just say "repeat the key indefinitely", and you'd
have an infinitely long keystream. Not infinite entropy, though.

The *FACT* that keys of different lengths can create same properties
and entropy of *STREAM* is due to use of permutations(shuffles) and
*KEYEXPANDING*

Nope. It's just handwaving and it is not a fact.

I think you very well understand the difference of these concepts.

I doubt anyone very well understands the concepts you are expressing,
because they are expressed in vauge and contradictory languange,
and are, frankly, wrong.


As long as you meant a maximum entropy of 8 bits then that is true.

But it looks like you are deriving entropy from a false source.

Well the key will never have more than 8 bit entropy.....

So neither will the keystream.

Except, a longer key would have more than 8 bits of entropy.

Either way, it seems you do not understand the principles of entropy,
or what someone means when they say they have, say, 80 bits of
entropy.

I know very well......

You don't understand entropy, do you?

Yes i do in a binary with the given length x the entropy is 2^x,

Uhm, no.

in
plaintext english the number of possible unique states a binarystring
of that *SPECIFIC LENGTH*

You should though try to decode the meaning of *SPECIFIC LENGTH* and
try to logically deduce the connection to *KEYEXPANSION* and
*SHUFFLES*

There is no need to try to "decode the meaning" of what you said,
as it's already wrong before you started using meaningless terms.

I do not hold high hopes that it will enlighten you, the least.

No, you're the one that needs enlightening.

I mean... you use the word constantly... but you appear to not
understand what it means, particularly as regards crypto.

Blah blah blah

Indeed. You _are_ a troll, and I'm giving up on this.

--
David Taylor
.

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