Do you think we should try and support this case in our API then @Ivoz? I 
think gcrypt has some support for this but I don't know about OpenSSL.

I guess we could do something along the lines of 
ECPrivateKey.signer(ECDSA/EdDSA(), SHA()) to cope with the different 
signature algorithms?


On 7 April 2014 21:05:11 Matt Iversen <notifications@github.com> wrote:

> > +    A named `ECDSA`_ curve.
> > +
> > +    .. attribute:: name
> > +
> > +        :type: string
> > +
> > +        The name of the curve. Usually the name defined by SECG. e.g. 
> secp256k1
> > +
> > +    .. attribute:: key_size
> > +
> > +        :type: int
> > +
> > +        The bit length of the curves base point.
> > +
> > +
> > +.. class:: ECDSAPrivateKey
>
> Well of course you can't use Ed25519 in ECDSA... That's EdDSA using Curve25519.
>
> Curve25519 itself is originally a Montgomery  curve which should work fine 
> for ECDSA. When you talk about Ed25519, you're actually talking about the 
> Twisted Edwards form of Curve25519 instead.
>
> The Go code you link @alex is the underlying ECC math operations on the 
> Montgomery form of 25519. As far as I can see Go uses it there for NaCl, 
> but has only implemented the crypto_box portion (which does ECDH) but not 
> the signature portion (which would be EdDSA).
>
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