New snapshot

[Damien Miller]

On Wed, 15 Nov 2000, Gert Doering wrote:

> My gripe is being *forced* to create multiple different host keys (or 
> disable protocol 2).

You are not forced to do anything. To enable protocol 2, you need either
a SSH2 DSA key, a SSH2 RSA key or both. 

RSA has a couple of advantages over DSA:

- Generating a DSA signature requires 160 bits of entropy (k), if these
bits are ever recovered or guessed by an attacker, then they can be used 
to determine your private key[1]. 

- The keys are shorter (you don't need to ship parameters about with 
the key as you do with DSA)

- Key generation is quicker (DSA parameter generation is slow and 
computationally intensive)

- Verification of signatures (and thus authentication) can be an order 
of magnitude faster with RSA. Signing is a little slower. OpenSSL
speaks best here:

                  sign    verify    sign/s verify/s
rsa 1024 bits   0.0165s   0.0009s     60.8   1138.9
dsa 1024 bits   0.0084s   0.0099s    118.7    101.1

Regards,
Damien Miller

[1] _Applied Cryptography_, Bruce Schneier, p. 492

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