Re: Golden Key Campaign

[Wei Dai <weidai@eskimo.com>]

On Wed, 24 Apr 1996, Hal wrote:

> Rabin encryption would have the advantage that it could be used with
> existing RSA keys as long as the modulus is a Blum modulus.  PGP at least
> has always used Blum moduli, perhaps for this eventuality.  So an
> alternative encryption program could use Rabin encryption and work with
> the existing infrastructure of PGP keys.  It would not of course be
> compatible with PGP for encryption and decryption.
> 
> This doesn't solve the signature problem; I'm not sure if there is a
> signature algorithm which could use RSA public keys but which is not
> covered by the RSA patent.  In any case since PGP key certificates use
> RSA signatures it would not appear to be possible to validate key
> signatures without infringing on the RSA patents, so that cancels out a
> lot of the advantages of using existing PGP keys.

You can do signatures with Rabin too.  I have a version of it in
Crypto++ 2.0.  It's been out for a while and RSA hasn't bothered me about
it.

Does anyone want to explain why, given the alternatives, people continue
to use RSA and pay for it?

Wei Dai