Re: How do I get RSA public key from X509Certificate ?

From: Kishore (kishorerc@hotmail.com)
Date: 07/25/02 

From: "Kishore" <kishorerc@hotmail.com>
Date: Wed, 24 Jul 2002 16:04:40 -0700

Allen,

I found out that the X509Certificate.GetPublicKey() actually returns the
Modulus and Exponent in a single byte[]. The modulus starts at position 5.
We will have to get the Modulus and Exponent from this byte[] and set it to
the RSAParameters object. Now the problem is how do we know how long the
Modulus will be ? Is there a spec which defines this ?

Now, for your question:
I did not understand your question properly. But let me tell you what I am
doing.

I am playing with the SSL 3.0 specification and trying to write an SSL
client library. The server sends all the certificates according to the
specification. I parse the input and create X509Certificate with the
content.

Thanks,
Kishore

"Allen Owen" <alleno@intenda.co.za> wrote in message
news:OZHWpZuMCHA.2244@tkmsftngp11...
> Hi Kishore,
>
> I use {1,0,1} for the exponent, but I can't be 100% sure that it's the
> correct way to go about it.
>
> A quick question for you though. Have you tried to retrieve the matching
> server certificate for the X509 cert?
> I'd imagine that you're getting your a client cert via
> Request.ClientCertificate and I need to retreive the matching server cert
> and thus far can't see a way to do it :( .
>
> Cheers
> Allen
>
>
> "Kishore" <kishorerc@hotmail.com> wrote in message
> news:ePCLqfsMCHA.488@tkmsftngp10...
> > Hi Everyone,
> > I have a X509Certificate, I want to get a RSA object using the public
key
> > from the cert. Is this code correct ?
> >
> > public RSA GetKey(X509Certificate cert)
> > {
> > RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
> > RSAParameters keyInfo = new RSAParameters();
> > keyInfo.Exponent = key;
> > keyInfo.Modulus = key;
> > rSA.ImportParameters(keyInfo);
> > return rsa;
> > }
> >
> > Or should I use {1,0,1} for the Exponent ?
> > Thanks,
> > Kishore
> >
> >
>
>

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