Long Key Performance

Justin Troutman justinrt at bellsouth.net
Sun Apr 21 17:14:01 CEST 2002

----- Original Message -----
From: Enzo Michelangeli <em at who.net>
To: <gnupg-devel at gnupg.org>
Sent: Sunday, April 21, 2002 6:33 AM
Subject: Re: Long Key Performance

> NIST, in the document
> http://csrc.nist.gov/encryption/dss/ecdsa/NISTReCur.pdf , explicitly
> suggests that for ECC keys one should use a number of bits roughly double
> than the symmetric cipher's keysize; and Certicom in 1999 (see e.g.
> http://www.scramdisk.clara.net/pgpfaq.html#SubElliptic ) published the
> following table of comparison:
> Block Cipher Keylength  RSA Key Length  EC Key Length
>  80                      1024           160
> 112                      2048           224
> 128                      3072           256
> 192                      7680           384
> 256                     15360           512

I read those documents understand the correlation of these size comparisons,
however, even though I believe this is so with a smaller sized comparison
like 1024-bit RSA to 80 bit symmetric, which I stated before, I don't
believe it is accurate for one to go much higher than that, as the
mathematics of symmetry and asymmetry (either RSA or ECC) both differ so
greatly, that it diminishes the value of comparing key sizes, in that the
systems attack/security properties are so different.

- Justin

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