PublicKey.Key Property

Definition

Caution

PublicKey.Key is obsolete. Use the appropriate method to get the public key, such as GetRSAPublicKey.

Gets an RSA derived object or a DSA derived object representing the public key.

C#
public System.Security.Cryptography.AsymmetricAlgorithm Key { get; }
C#
[System.Obsolete("PublicKey.Key is obsolete. Use the appropriate method to get the public key, such as GetRSAPublicKey.", DiagnosticId="SYSLIB0027", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public System.Security.Cryptography.AsymmetricAlgorithm Key { get; }

Property Value

An AsymmetricAlgorithm object representing the public key.

Attributes

Exceptions

The key algorithm is not supported.

Examples

The following code example opens the current user certificate store, selects only active certificates, and then allows the user to select one or more certificates. The example then writes certificate information to the console.

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

class CertSelect
{
    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)
        {
            try
            {
                byte[] rawdata = x509.RawData;
                Console.WriteLine("Content Type: {0}{1}",X509Certificate2.GetCertContentType(rawdata),Environment.NewLine);
                Console.WriteLine("Friendly Name: {0}{1}",x509.FriendlyName,Environment.NewLine);
                Console.WriteLine("Certificate Verified?: {0}{1}",x509.Verify(),Environment.NewLine);
                Console.WriteLine("Simple Name: {0}{1}",x509.GetNameInfo(X509NameType.SimpleName,true),Environment.NewLine);
                Console.WriteLine("Signature Algorithm: {0}{1}",x509.SignatureAlgorithm.FriendlyName,Environment.NewLine);
                Console.WriteLine("Public Key: {0}{1}",x509.PublicKey.Key.ToXmlString(false),Environment.NewLine);
                Console.WriteLine("Certificate Archived?: {0}{1}",x509.Archived,Environment.NewLine);
                Console.WriteLine("Length of Raw Data: {0}{1}",x509.RawData.Length,Environment.NewLine);
                X509Certificate2UI.DisplayCertificate(x509);
                x509.Reset();
            }
            catch (CryptographicException)
            {
                Console.WriteLine("Information could not be written out for this certificate.");
            }
        }
        store.Close();
    }
}

Remarks

This property returns the public key. Both RSA and DSA keys are supported. Call this property to obtain a certificate's public key. Repeated calls to this property will return the same key.

Applies to

Product Versions (Obsolete)
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5 (6, 7, 8, 9)
.NET Framework 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1