Default private ECC key generated via step is not compatible with .net framework. Giving unsupported PrivateKey exception of type 'System.NotSupportedException' about cli

[hslatman]

How are you using the EC key? Have you tried RSA too, and confirmed that's working? Do you have some example code of how you're trying to use it?

[neetabisht]

Regarding ECC key:
public static async Task connect_with_pub()
{
string x509_pem = @"C:\Users\INNEBIS1/client1-authn-ID.pem";
string x509_key = @"C:\Users\INNEBIS1/client1-authn-ID.key";

    // Load certificate and private key from PEM files
    var certificate = new X509Certificate2(X509Certificate2.CreateFromPemFile(x509_pem, x509_key).Export(X509ContentType.Pkcs12));

Here when I try to extract the values inside certificate then i see

Regarding RSA: I tried creating pem and key file using below command and tried checking the values of certificate there I am not seeing any issue.
step certificate create client1-authn-ID client1-authn-ID.pem client1-authn-ID.key --ca ../.step/certs/intermediate_ca.crt
--ca-key ../.step/secrets/intermediate_ca_key --no-password --insecure --not-after 2400h --kty RSA --size 2048

So eventually i am not seeing any error when creating cert files using RSA algo but facing issue when "step" default create the cert file with ECC with .net framework.

[hslatman]

According to this StackOverflow thread, new X509Certificate2 doesn't support EC: https://stackoverflow.com/questions/45107057/creating-x509certificate2-from-ecc-x509certificate-throws-system-notsupportedex.

This blog has some alternatives: https://www.scottbrady91.com/c-sharp/ecdsa-key-loading.