RSA / DSS (keylenghts)

Mr. B
Thu, 21 Sep 2000 18:57:52 -0700

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On Thu, Sep 21, 2000 at 05:53:38PM +0100, Pete Chown wrote:

> Ralf Senderek wrote:
> > if you double the size of a DSS-key not one additional secret key value
> > is added because the amount of possible secret keys is limited by the
> > size of the hash-function (160 bits), Only the mathematical operation=
> > will use a longer key (as modulus) and consequently takes more time.
> This is true, but hopefully it makes cryptanalysis more difficult. By
> the time you get to a 1024-bit modulus, it will take roughly the same
> amount of time to solve either of the two possible discrete logarithm
> problems. With a 512-bit modulus, it is (counterintuitively) much
> easier to attack the 512-bit discrete logarithm problem rather than
> the 160-bit one, because they have different characteristics. (I am
> sure you already knew that though.)
> There is no reason why you couldn't have a DSA key longer than 1024
> bits (that I am aware of). However, to get any benefit from this you
> would need to make the other modulus longer than 160 bits. This would
> mean using a hash function other than SHA-1, for example Tiger/192.
> --=20
> Pete
> --=20
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So... what functionality did the gpg RSA upgrade really give us anyway? Roger Brown --=20 Get paid to spread the word... Help distribute the Planetary Appeal. PADN - Planetary Appeal Distribution Network --PEIAKu/WMn1b1Hv9 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.3 (GNU/Linux) Comment: For info see iD8DBQE5yryg8EpIbKkWFucRAj42AJ9oQTQFIx0PB23A2mHBWvFifGhXrQCbByYO FToiuBlfXFbfLXRjWlOtVso= =G50h -----END PGP SIGNATURE----- --PEIAKu/WMn1b1Hv9-- -- Archive is at - Unsubscribe by sending mail with a subject of "unsubscribe" to