X509Certificate2.NotBefore Property

using System;
using System.Security.Cryptography;
using System.Security.Permissions;
using System.IO;
using System.Security.Cryptography.X509Certificates;


class CertInfo
{
	//Reads a file.
	internal static byte[] ReadFile (string fileName)
	{
		FileStream f = new FileStream(fileName, FileMode.Open, FileAccess.Read);
		int size = (int)f.Length;
		byte[] data = new byte[size];
		size = f.Read(data, 0, size);
		f.Close();
		return data;
	}
	//Main method begins here.
	static void Main(string[] args)
	{
		//Test for correct number of arguments.
		if (args.Length < 1)
		{
			Console.WriteLine("Usage: CertInfo <filename>");
			return;
		}
		try
		{
			X509Certificate2 x509 = new X509Certificate2();
			//Create X509Certificate2 object from .cer file.
			byte[] rawData = ReadFile(args[0]);

			x509.Import(rawData);

			//Print to console information contained in the certificate.
			Console.WriteLine("{0}Subject: {1}{0}", Environment.NewLine,x509.Subject);
			Console.WriteLine("{0}Issuer: {1}{0}", Environment.NewLine,x509.Issuer);
			Console.WriteLine("{0}Version: {1}{0}", Environment.NewLine,x509.Version);
			Console.WriteLine("{0}Valid Date: {1}{0}", Environment.NewLine,x509.NotBefore);
			Console.WriteLine("{0}Expiry Date: {1}{0}", Environment.NewLine,x509.NotAfter);
			Console.WriteLine("{0}Thumbprint: {1}{0}", Environment.NewLine,x509.Thumbprint);
			Console.WriteLine("{0}Serial Number: {1}{0}", Environment.NewLine,x509.SerialNumber);
			Console.WriteLine("{0}Friendly Name: {1}{0}", 								Environment.NewLine,x509.PublicKey.Oid.FriendlyName);
			Console.WriteLine("{0}Public Key Format: {1}{0}", 											Environment.NewLine,x509.PublicKey.EncodedKeyValue.Format(true));
			Console.WriteLine("{0}Raw Data Length: {1}{0}", Environment.NewLine,x509.RawData.Length);
			Console.WriteLine("{0}Certificate to string: {1}{0}", Environment.NewLine,x509.ToString(true));

			Console.WriteLine("{0}Certificate to XML String: {1}{0}", 								Environment.NewLine,x509.PublicKey.Key.ToXmlString(false));

			//Add the certificate to a X509Store.
			X509Store store = new X509Store();
			store.Open(OpenFlags.MaxAllowed);
			store.Add(x509);
			store.Close();
		}

		catch (DirectoryNotFoundException)
			{
				   Console.WriteLine("Error: The directory specified could not be found.");
			}
		catch (IOException)
			{
				Console.WriteLine("Error: A file in the directory could not be accessed.");
			}
		catch (NullReferenceException)
			{
				Console.WriteLine("File must be a .cer file. Program does not have access to that type of file.");
			}
	}

}