Re: Why is AES more secure than DES??
From: Simon Johnson (Ckwop_at_hotmail.com)
Date: 04/30/03
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Date: 30 Apr 2003 06:33:29 -0700
"Yuen" <Yuen@123.com> wrote in message news:<MRsra.24777$1s1.380171@newsfeeds.bigpond.com>...
> I encrypt a block of data 0xFFF times, the result:
> AES128 0.0200(seconds)
> AES256 0.0200(seconds)
> DES 0.4500 (seconds)
>
> AES is much faster, but why is AES more secure than DES??
In short, we don't know it is any more secure. It is *possible* that
DES is more secure than AES.. though the evidence available suggests
it's not.
> When cracking a message, faster decryption is easier to crack?? because one
> can guess more password per second.
> The cracking method is "guess all possible password"
Against this attack, AES is alot more secure simply because the number
of keys is huge. There are 2^72 times as many keys for AES as there
are for DES. Even though testing each key may be faster.. you have to
test a huge number of additonal keys.
It is important to realise that the strength of a cipher is not
dependant on only the key. The key size gives you the *maximum* amount
of work required to break the cipher.. There could be mathematical
tricks that allow you to find the key alot faster than this maximum.
It is trying to prevent such tricks being deployed that makes real
world cipher design difficult.
Yours,
Simon.
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