Dump information about expired certificates from the Windows Certificate Store

DumpExpiredCerts.cs

using System;
using System.Security.Cryptography.X509Certificates;

namespace DumpExpiredCertificates
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            // Iterates through all of the X.509 digital certificates installed in the certificate store
            // on a Windows operating system, dumping out some metadata about each. Each certificate, in
            // each Certificate Store, from each Certificate Location is included.
            //
            // Bill Wilder | @codingoutloud | Nov 2012
            // Original: https://gist.github.com/4179954

            var totalCerts = 0;
            var totalExpiredCerts = 0;
            var totalNotYetValidCerts = 0;

            foreach (var sl in Enum.GetValues(typeof (StoreLocation)))
            {
                Console.WriteLine(String.Format("Store Location: {0}", sl));
                foreach (var sn in Enum.GetValues(typeof (StoreName)))
                {
                    var store = new X509Store((StoreName) sn, (StoreLocation) sl);
                    store.Open(OpenFlags.ReadOnly);

                    Console.WriteLine(String.Format(" Store Location/Store Name: {0}/{1}",
                                                    store.Location, store.Name));
                    foreach (X509Certificate2 c in store.Certificates)
                    {
                        totalCerts++;

                        var now = DateTime.UtcNow;
                        if (c.NotAfter < now || c.NotBefore > now)
                        {
                            // Certificate c has expired or not yet become valid

                            if (c.NotAfter < now) totalExpiredCerts++;
                            if (c.NotBefore > now) totalNotYetValidCerts++;

                            Console.WriteLine(String.Format("{0} {1}/{2} {0}",
                                                            new string('-', 15), store.Location, store.Name));
                            Console.WriteLine("{0}" +
                                              "\tCertificate Subject Name: {1}" +
                                              "\n\t Has private key? {2} Is archived? {3}" +
                                              "\n\t X.509 version: {4}" +
                                              "\n\t Key algorithm: {5} Signature algorithm: {6}" +
                                              "\n\t Issuer: {7}" +
                                              "\n\t Invalid before: {8}" +
                                              "\n\t Invalid after: {9}" +
                                              "\n\t {10} extensions",
                                              String.IsNullOrEmpty(c.FriendlyName)
                                                  ? ""
                                                  : String.Format("\t[Store Friendly Name: {0}]\n",
                                                                  c.FriendlyName),
                                              c.SubjectName.Name,
                                              // FriendlyName is a store concept, not cert?
                                              c.HasPrivateKey, c.Archived,
                                              c.Version,
                                              c.GetKeyAlgorithm(), c.SignatureAlgorithm,
                                              c.IssuerName.Name,
                                              c.NotBefore, c.NotAfter,
                                              c.Extensions.Count);
                            foreach (var ext in c.Extensions)
                            {
                                Console.WriteLine("\t OID = {0} {1}", ext.Oid.FriendlyName,
                                                  ext.Critical ? "[Critical]" : "");
                            }
                        }
                    }
                    store.Close();
                }
            }

            Console.WriteLine("\nFor Operating System {0}...\n", Environment.OSVersion);
            Console.WriteLine("Of {0} total certificates, {1} are not YET valid, {2} have EXPIRED.",
                              totalCerts, totalNotYetValidCerts, totalExpiredCerts);
            Console.ReadLine();
        }
    }
}