This documentation is archived and is not being maintained.

X500DistinguishedName Class

Represents the distinguished name of an X509 certificate. This class cannot be inherited.


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

public sealed class X500DistinguishedName : AsnEncodedData

The X500DistinguishedName type exposes the following members.

Public methodX500DistinguishedName(AsnEncodedData)Initializes a new instance of the X500DistinguishedName class using the specified AsnEncodedData object.
Public methodX500DistinguishedName(Byte[])Initializes a new instance of the X500DistinguishedName class using information from the specified byte array.
Public methodX500DistinguishedName(String)Initializes a new instance of the X500DistinguishedName class using information from the specified string.
Public methodX500DistinguishedName(X500DistinguishedName)Initializes a new instance of the X500DistinguishedName class using the specified X500DistinguishedName object.
Public methodX500DistinguishedName(String, X500DistinguishedNameFlags)Initializes a new instance of the X500DistinguishedName class using the specified string and X500DistinguishedNameFlags flag.

Public propertyNameGets the comma-delimited distinguished name from an X500 certificate.
Public propertyOidGets or sets the Oid value for an AsnEncodedData object. (Inherited from AsnEncodedData.)
Public propertyRawDataGets or sets the Abstract Syntax Notation One (ASN.1)-encoded data represented in a byte array. (Inherited from AsnEncodedData.)

Public methodCopyFromCopies information from an AsnEncodedData object. (Inherited from AsnEncodedData.)
Public methodDecodeDecodes a distinguished name using the characteristics specified by the flag parameter.
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodFormatReturns a formatted version of an X500 distinguished name for printing or for output to a text window or to a console. (Overrides AsnEncodedData.Format(Boolean).)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)

This class is like an extension to the SubjectName or IssuerName property, which is the name of the person or entity that the certificate is being issued to. X.500 is an international standard for distributed directory services. The distinguished name uses the following format:


The following field length limits apply:


Length Limit


2 characters


Up to 64 characters


Up to 32 characters


Up to 64 characters

The following guidelines apply:

  • Field values can be uppercase or lowercase.

  • Delimiters are slash marks (/) and must appear before the first value and between subsequent values.

  • Delimiters can be followed by a space.

The following is an example of a correctly formatted name: [X500:/ C=US/ O=Microsoft/ OU=WGA/ CN=TedSt]

The following code example shows how to use the X500DistinguishedName class.

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

class X500Sample
	static void Main()
			X509Store store = new X509Store("MY", StoreLocation.CurrentUser);
			store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);
			X509Certificate2Collection collection = (X509Certificate2Collection)store.Certificates;
			X509Certificate2Collection fcollection = (X509Certificate2Collection)collection.Find(X509FindType.FindByTimeValid, DateTime.Now, false);
			X509Certificate2Collection scollection = X509Certificate2UI.SelectFromCollection(fcollection, "Test Certificate Select", "Select a certificate from the following list to get information on that certificate", X509SelectionFlag.MultiSelection);
			Console.WriteLine("Number of certificates: {0}{1}", scollection.Count, Environment.NewLine);
			foreach (X509Certificate2 x509 in scollection)
				X500DistinguishedName dname = new X500DistinguishedName(x509.SubjectName);
				Console.WriteLine("X500DistinguishedName: {0}{1}", dname.Name, Environment.NewLine);
		catch (CryptographicException)
			Console.WriteLine("Information could not be written out for this certificate.");


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.