Export a given server certificate chain into local independent files

TlsServerCertificateChainExporter.ps1

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'
trap {
    Write-Output "ERROR: $_"
    Write-Output (($_.ScriptStackTrace -split '\r?\n') -replace '^(.*)$','ERROR: $1')
    Write-Output (($_.Exception.ToString() -split '\r?\n') -replace '^(.*)$','ERROR EXCEPTION: $1')
    Exit 1
}

Add-Type @'
using System;
using System.IO;
using System.Linq;
using System.Net.Security;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;

public class TlsServerCertificateChainExporter
{
    public static void Export(string serverName, int serverPort)
    {
        var certificatePathPrefix = serverName;

        Console.WriteLine("Establishing TCP connection to the {0} server...", serverName);
        using (var client = new TcpClient(serverName, serverPort))
        {
            Console.WriteLine("Establishing TLS connection...");
            using (var sslStream = new SslStream(
                client.GetStream(),
                false,
                (object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) =>
                {
                    if (sslPolicyErrors == SslPolicyErrors.None)
                    {
                        Console.WriteLine("The server certificate validated successfully.");
                    }
                    else
                    {
                        Console.WriteLine("The server certificate validation failed with the {0} errors.", sslPolicyErrors);
                    }

                    Console.WriteLine("Saving the server certificate chain into separate {0}-*.der files...", certificatePathPrefix);
                    foreach (var elementWithIndex in chain.ChainElements.Cast<X509ChainElement>().Select((e, i) => new { e, i }))
                    {
                        File.WriteAllBytes(
                            string.Format("{0}-{1}.der", certificatePathPrefix, elementWithIndex.i),
                            elementWithIndex.e.Certificate.Export(X509ContentType.Cert));
                    }

                    // always allow the connection to go through.
                    return true;
                },
                null))
            {
                Console.WriteLine("Authenticating the server...");
                sslStream.AuthenticateAsClient(serverName);
            }
        }
    }
}
'@

[TlsServerCertificateChainExporter]::Export('httpbin.org', 443)