Authenticate the KEY File in Certificate using C#

Akaash Chintamani Meher

3y898C#

As in Postman we have certificate and key file, how do I validate the KEY file using c# or MVC. I have tried adding the below code but seems like for the KEY file we've some other code to write. Please suggest some help.

string base64cert = Convert.ToBase64String(File.ReadAllBytes(pemFilePath));
var cert = new X509Certificate2(Convert.FromBase64String(base64cert), certAuthCode);
cert.PrivateKey = null;
handler.ClientCertificates.Add(cert);
handler.ClientCertificateOptions = ClientCertificateOption.Manual;
handler.SslProtocols = SslProtocols.Tls12;
handler.ClientCertificates.Add(new X509Certificate2(crtFilePath));
//For Key File Path
handler.ClientCertificates.Add(new X509Certificate2(crtKeyPath));

3 Replies

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Amit Mohanty3y ago

Try this

private static RSACryptoServiceProvider LoadPrivateKey(byte[] keyBytes)
{
    var rsa = new RSACryptoServiceProvider();
    rsa.ImportCspBlob(keyBytes);
    return rsa;
}

Akaash Chintamani Meher3y ago
@Amit Mohanty - Thanks for the response. I think the ImportPkcs8PrivateKey() method is available in higher version of .Net because I'm getting error for the same. Could you please provide any alternatives.
0

Amit Mohanty3y ago

Please take a look at the code below; it may be helpful to you.

var keyBytes = File.ReadAllBytes(crtKeyPath);
cert.PrivateKey = DecodePrivateKey(keyBytes);

// Function to decode the private key from the file bytes
private static AsymmetricAlgorithm DecodePrivateKey(byte[] keyBytes)
{
    var rsa = RSA.Create();
    rsa.ImportPkcs8PrivateKey(keyBytes, out _);
    return rsa;
}