Exporting a Certificate as BASE-64 encoded .cer

Question

I am trying to export a cert without the private key as as BASE-64 encoded file, same as exporting it from windows. When exported from windows I am able to open the .cer file in notepad.

When I try the following and open on notepad I get binary data...I think it is...not readable.

X509Certificate2 cert = new X509Certificate2("c:\\myCert.pfx", "test", X509KeyStorageFlags.Exportable);

File.WriteAllBytes("c:\\testcer.cer", cert.Export(X509ContentType.Cert));

I tried removing the 'X509KeyStorageFlags.Exportable" but that doesn't work. Am I missing something?

Edit - I tried

File.WriteAllText("c:\\testcer.cer",Convert.ToBase64String(cert.Export(X509ContentType.Cert)))

and that seems to work, however, missing the "-----BEGIN CERTIFICATE-----" and "-----END CERTIFICATE-----"

Answer 1

Perhaps

/// <summary>
/// Export a certificate to a PEM format string
/// </summary>
/// <param name="cert">The certificate to export</param>
/// <returns>A PEM encoded string</returns>
public static string ExportToPEM(X509Certificate cert)
{
    StringBuilder builder = new StringBuilder();            

    builder.AppendLine("-----BEGIN CERTIFICATE-----");
    builder.AppendLine(Convert.ToBase64String(cert.Export(X509ContentType.Cert), Base64FormattingOptions.InsertLineBreaks));
    builder.AppendLine("-----END CERTIFICATE-----");

    return builder.ToString();
}