X509Certificate Constructor Exception

Question

//cert is an EF Entity and 
//    cert.CertificatePKCS12 is a byte[] with the certificate.

var certificate = new X509Certificate(cert.CertificatePKCS12, \"SomePassw         


        

Answer 1

The following code will help you, you can generate algorithm using bouncy castle library:

private static ECDsa GetEllipticCurveAlgorithm(string privateKey)
{
    var keyParams = (ECPrivateKeyParameters)PrivateKeyFactory
        .CreateKey(Convert.FromBase64String(privateKey));

    var normalizedECPoint = keyParams.Parameters.G.Multiply(keyParams.D).Normalize();

    return ECDsa.Create(new ECParameters
    {
        Curve = ECCurve.CreateFromValue(keyParams.PublicKeyParamSet.Id),
        D = keyParams.D.ToByteArrayUnsigned(),
        Q =
    {
        X = normalizedECPoint.XCoord.GetEncoded(),
        Y = normalizedECPoint.YCoord.GetEncoded()
    }
    });
}

and generate the token in the following way:

var signatureAlgorithm = GetEllipticCurveAlgorithm(privateKey);

        ECDsaSecurityKey eCDsaSecurityKey = new ECDsaSecurityKey(signatureAlgorithm)
        {
            KeyId = settings.Apple.KeyId
        };

        var handler = new JwtSecurityTokenHandler();   
        var token = handler.CreateJwtSecurityToken(
            issuer: iss,
            audience: AUD,
            subject: new ClaimsIdentity(new List { new Claim("sub", sub) }),
            expires: DateTime.UtcNow.AddMinutes(5), 
            issuedAt: DateTime.UtcNow,
            notBefore: DateTime.UtcNow,
            signingCredentials: new SigningCredentials(eCDsaSecurityKey, SecurityAlgorithms.EcdsaSha256));