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X509Certificate2.SerialNumber Property

Gets the serial number of a certificate.

Namespace:  System.Security.Cryptography.X509Certificates
Assembly:  System (in System.dll)

public string SerialNumber { get; }

Property Value

Type: System.String
The serial number of the certificate.

The serial number of the certificate is part of the original X.509 protocol. The serial number is a unique number issued by the certificate issuer, which is also called the Certificate Authority (CA).

The following code example creates a command-line executable that takes a certificate file as an argument and prints various certificate properties to the console.

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.");
			}
	}

}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0
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