PublicKey Class

Represents a certificate's public key information. This class cannot be inherited.

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

'Declaration
Public NotInheritable Class PublicKey
'Usage
Dim instance As PublicKey

public final class PublicKey
public final class PublicKey
Not applicable.

The PublicKey object contains the object identifier (Oid) representing the public key algorithm, the ASN-encoded parameters, and the ASN.1-encoded key value.

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.

Imports System
Imports System.Security.Cryptography
Imports System.Security.Permissions
Imports System.IO
Imports System.Security.Cryptography.X509Certificates
Imports Microsoft.VisualBasic




Class CertInfo

    'Reads a file.
    Friend Shared Function ReadFile(ByVal fileName As String) As Byte()
        Dim f As New FileStream(fileName, FileMode.Open, FileAccess.Read)
        Dim size As Integer = Fix(f.Length)
        Dim data(size) As Byte
        size = f.Read(data, 0, size)
        f.Close()
        Return data

    End Function 

    <SecurityPermission(SecurityAction.LinkDemand, Unrestricted:=True)> _
    Shared Sub Main(ByVal args() As String)
        'Test for correct number of arguments.
        If args.Length < 1 Then
            Console.WriteLine("Usage: CertInfo <filename>")
            Return
        End If
        Try
            Dim x509 As New X509Certificate2()
            'Create X509Certificate2 object from .cer file.
            Dim rawData As Byte() = 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.
            Dim store As New X509Store()
            store.Open(OpenFlags.MaxAllowed)
            store.Add(x509)
            store.Close()

        Catch dnfExcept As DirectoryNotFoundException
            Console.WriteLine("Error: The directory specified could not be found.")
        Catch ioExpcept As IOException
            Console.WriteLine("Error: A file in the directory could not be accessed.")
        Catch nrExcept As NullReferenceException
            Console.WriteLine("File must be a .cer file. Program does not have access to that type of file.")
        End Try

    End Sub
End Class

import System.*;
import System.Security.Cryptography.*;
import System.Security.Permissions.*;
import System.IO.*;
import System.Security.Cryptography.X509Certificates.*;

//Permission demand to access files in c:\Test directory with.cer suffix.
/** @assembly FileIOPermissionAttribute(SecurityAction.RequestMinimum,
    All = "C:\\Test#@@#.cer")
 */

class CertInfo
{
    //Reads a file.
    static ubyte[] ReadFile(String fileName)
    {
        FileStream f = new FileStream(fileName, FileMode.Open, FileAccess.Read);
        int size = (int)(f.get_Length());
        ubyte data[] = new ubyte[size];

        size = f.Read(data, 0, size);
        f.Close();
        return data;
    } //ReadFile

	/** @attribute SecurityPermission(SecurityAction.LinkDemand,
		Unrestricted = true) */
    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.
            ubyte rawData[] = ReadFile(args[0]);

            x509.Import(rawData);

            //Print to console information contained in the certificate.
            Console.WriteLine("{0}Subject: {1}{0}", Environment.get_NewLine(),
                x509.get_Subject());
            Console.WriteLine("{0}Issuer: {1}{0}", Environment.get_NewLine(),
                x509.get_Issuer());
            Console.WriteLine("{0}Version: {1}{0}", Environment.get_NewLine(),
                (Int32)x509.get_Version());
            Console.WriteLine("{0}Valid Date: {1}{0}",
                Environment.get_NewLine(), x509.get_NotBefore());
            Console.WriteLine("{0}Expiry Date: {1}{0}",
                Environment.get_NewLine(), x509.get_NotAfter());
            Console.WriteLine("{0}Thumbprint: {1}{0}",
                Environment.get_NewLine(), x509.get_Thumbprint());
            Console.WriteLine("{0}Serial Number: {1}{0}",
                Environment.get_NewLine(), x509.get_SerialNumber());
            Console.WriteLine("{0}Friendly Name: {1}{0}",
                Environment.get_NewLine(),
                x509.get_PublicKey().get_Oid().get_FriendlyName());
            Console.WriteLine("{0}Public Key Format: {1}{0}",
                Environment.get_NewLine(),
                x509.get_PublicKey().get_EncodedKeyValue().Format(true));
            Console.WriteLine("{0}Raw Data Length: {1}{0}",
                Environment.get_NewLine(), (Int32)x509.get_RawData().length);
            Console.WriteLine("{0}Certificate to string: {1}{0}",
                Environment.get_NewLine(), x509.ToString(true));
            Console.WriteLine("{0}Certificate to XML String: {1}{0}",
                Environment.get_NewLine(),
                x509.get_PublicKey().get_Key().ToXmlString(false));

            //Add the certificate to a X509Store.
            X509Store store = new X509Store();
            store.Open(OpenFlags.MaxAllowed);
            store.Add(x509);
            store.Close();
        }
        catch (DirectoryNotFoundException exp) {
            Console.WriteLine("Error: The directory specified "
                + "could not be found.");
        }
        catch (IOException exp) {
            Console.WriteLine("Error: A file in the directory "
                + "could not be accessed.");
        }
        catch (NullReferenceException exp) {
            Console.WriteLine("File must be a.cer file. "
                + "Program does not have access to that type of file.");
        }
    } //main
} //CertInfo

System.Object
  System.Security.Cryptography.X509Certificates.PublicKey

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

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

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

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