Key size overkill

Key size overkill

Post by Nic » Sun, 20 Jul 2003 19:48:49


> I've been doing some calculations (yes - I know I'm sad).
Dont know about ur calculations, but how can it be overkill. The mo secure the better.

I just CANT fine the disadvantages of large(r) keys?
 
 
 

Key size overkill

Post by Tom McCun » Sun, 20 Jul 2003 21:10:49

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"Gamma3000" < XXXX@XXXXX.COM > wrote in



You are confusing symmetric and asymmetric encryption. See:
http://www.yqcomputer.com/ #128bit

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Key size overkill

Post by Neil W Ric » Sun, 20 Jul 2003 22:50:58

"Gamma3000" < XXXX@XXXXX.COM > writes:




Presumably the 128 bits is for symmetric keys, and the 2048 bits is
for public/private keys. A direct comparison of key sizes is
unreasonable, due to the differences in methodologies and
constraints.

While any random 128 bits can be used as a symmetric key, most 2048
bit strings would not be usable as an rsa key (to take one example).
 
 
 

Key size overkill

Post by Alex » Mon, 21 Jul 2003 03:09:12

On Sat, 19 Jul 2003 18:33:12 +0100





The difference is that factoring a public key lets you calculate the
private key. It's easier to factor a key than to try all possible keys
with the same length. Thus, the public/private pairs need to be larger
than a symmetric key for the same security.

--Alex
 
 
 

Key size overkill

Post by Gamma300 » Mon, 21 Jul 2003 18:44:04


me,

Got it. Symmetric and Asymmetric keys aren't equal. 128 bit symmetric
encryption is about as easy to brute force as 2304 bit asymmetric
encryption.

- PGP Attack FAQ


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