internal ECDsaCng MakeECDsa(COSE.Algorithm alg, COSE.EllipticCurve crv)
{
ECCurve curve;
switch (alg)
{
case COSE.Algorithm.ES256:
switch (crv)
{
case COSE.EllipticCurve.P256:
case COSE.EllipticCurve.P256K:
curve = ECCurve.NamedCurves.nistP256;
break;
default:
throw new ArgumentOutOfRangeException(string.Format("Missing or unknown crv {0}", crv.ToString()));
}
break;
case COSE.Algorithm.ES384:
switch (crv) // https://www.iana.org/assignments/cose/cose.xhtml#elliptic-curves
{
case COSE.EllipticCurve.P384:
curve = ECCurve.NamedCurves.nistP384;
break;
default:
throw new ArgumentOutOfRangeException(string.Format("Missing or unknown crv {0}", crv.ToString()));
}
break;
case COSE.Algorithm.ES512:
switch (crv) // https://www.iana.org/assignments/cose/cose.xhtml#elliptic-curves
{
case COSE.EllipticCurve.P521:
curve = ECCurve.NamedCurves.nistP521;
break;
default:
throw new ArgumentOutOfRangeException(string.Format("Missing or unknown crv {0}", crv.ToString()));
}
break;
default:
throw new ArgumentOutOfRangeException(string.Format("Missing or unknown alg {0}", alg.ToString()));
}
return(new ECDsaCng(curve));
}
