X509Certificate2 Class

Definition

Namespace:

System.Security.Cryptography.X509Certificates

Assembly:

System.Security.Cryptography.dll

Source:

X509Certificate2.cs

Represents an X.509 certificate.

public ref class X509Certificate2 : System::Security::Cryptography::X509Certificates::X509Certificate

public class X509Certificate2 : System.Security.Cryptography.X509Certificates.X509Certificate

type X509Certificate2 = class
    inherit X509Certificate

Public Class X509Certificate2
Inherits X509Certificate

Inheritance

Object

X509Certificate

X509Certificate2

Examples

The following example demonstrates how to use an X509Certificate2 object to encrypt and decrypt a file.

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

// To run this sample use the Certificate Creation Tool (Makecert.exe) to generate a test X.509 certificate and
// place it in the local user store.
// To generate an exchange key and make the key exportable run the following command from a Visual Studio command prompt:

//makecert -r -pe -n "CN=CERT_SIGN_TEST_CERT" -b 01/01/2010 -e 01/01/2012 -sky exchange -ss my
namespace X509CertEncrypt
{
    class Program
    {

        // Path variables for source, encryption, and
        // decryption folders. Must end with a backslash.
        private static string encrFolder = @"C:\Encrypt\";
        private static string decrFolder = @"C:\Decrypt\";
        private static string originalFile = "TestData.txt";
        private static string encryptedFile = "TestData.enc";

        static void Main(string[] args)
        {

            // Create an input file with test data.
            StreamWriter sw = File.CreateText(originalFile);
            sw.WriteLine("Test data to be encrypted");
            sw.Close();

            // Get the certificate to use to encrypt the key.
            X509Certificate2 cert = GetCertificateFromStore("CN=CERT_SIGN_TEST_CERT");
            if (cert == null)
            {
                Console.WriteLine("Certificate 'CN=CERT_SIGN_TEST_CERT' not found.");
                Console.ReadLine();
            }

            // Encrypt the file using the public key from the certificate.
            EncryptFile(originalFile, (RSA)cert.PublicKey.Key);

            // Decrypt the file using the private key from the certificate.
            DecryptFile(encryptedFile, cert.GetRSAPrivateKey());

            //Display the original data and the decrypted data.
            Console.WriteLine("Original:   {0}", File.ReadAllText(originalFile));
            Console.WriteLine("Round Trip: {0}", File.ReadAllText(decrFolder + originalFile));
            Console.WriteLine("Press the Enter key to exit.");
            Console.ReadLine();
        }
        private static X509Certificate2 GetCertificateFromStore(string certName)
        {

            // Get the certificate store for the current user.
            X509Store store = new X509Store(StoreLocation.CurrentUser);
            try
            {
                store.Open(OpenFlags.ReadOnly);

                // Place all certificates in an X509Certificate2Collection object.
                X509Certificate2Collection certCollection = store.Certificates;
                // If using a certificate with a trusted root you do not need to FindByTimeValid, instead:
                // currentCerts.Find(X509FindType.FindBySubjectDistinguishedName, certName, true);
                X509Certificate2Collection currentCerts = certCollection.Find(X509FindType.FindByTimeValid, DateTime.Now, false);
                X509Certificate2Collection signingCert = currentCerts.Find(X509FindType.FindBySubjectDistinguishedName, certName, false);
                if (signingCert.Count == 0)
                    return null;
                // Return the first certificate in the collection, has the right name and is current.
                return signingCert[0];
            }
            finally
            {
                store.Close();
            }
        }

        // Encrypt a file using a public key.
        private static void EncryptFile(string inFile, RSA rsaPublicKey)
        {
            using (Aes aes = Aes.Create())
            {
                // Create instance of Aes for
                // symmetric encryption of the data.
                aes.KeySize = 256;
                aes.Mode = CipherMode.CBC;
                using (ICryptoTransform transform = aes.CreateEncryptor())
                {
                    RSAPKCS1KeyExchangeFormatter keyFormatter = new RSAPKCS1KeyExchangeFormatter(rsaPublicKey);
                    byte[] keyEncrypted = keyFormatter.CreateKeyExchange(aes.Key, aes.GetType());

                    // Create byte arrays to contain
                    // the length values of the key and IV.
                    byte[] LenK = new byte[4];
                    byte[] LenIV = new byte[4];

                    int lKey = keyEncrypted.Length;
                    LenK = BitConverter.GetBytes(lKey);
                    int lIV = aes.IV.Length;
                    LenIV = BitConverter.GetBytes(lIV);

                    // Write the following to the FileStream
                    // for the encrypted file (outFs):
                    // - length of the key
                    // - length of the IV
                    // - encrypted key
                    // - the IV
                    // - the encrypted cipher content

                    int startFileName = inFile.LastIndexOf("\\") + 1;
                    // Change the file's extension to ".enc"
                    string outFile = encrFolder + inFile.Substring(startFileName, inFile.LastIndexOf(".") - startFileName) + ".enc";
                    Directory.CreateDirectory(encrFolder);

                    using (FileStream outFs = new FileStream(outFile, FileMode.Create))
                    {

                        outFs.Write(LenK, 0, 4);
                        outFs.Write(LenIV, 0, 4);
                        outFs.Write(keyEncrypted, 0, lKey);
                        outFs.Write(aes.IV, 0, lIV);

                        // Now write the cipher text using
                        // a CryptoStream for encrypting.
                        using (CryptoStream outStreamEncrypted = new CryptoStream(outFs, transform, CryptoStreamMode.Write))
                        {

                            // By encrypting a chunk at
                            // a time, you can save memory
                            // and accommodate large files.
                            int count = 0;

                            // blockSizeBytes can be any arbitrary size.
                            int blockSizeBytes = aes.BlockSize / 8;
                            byte[] data = new byte[blockSizeBytes];
                            int bytesRead = 0;

                            using (FileStream inFs = new FileStream(inFile, FileMode.Open))
                            {
                                do
                                {
                                    count = inFs.Read(data, 0, blockSizeBytes);
                                    outStreamEncrypted.Write(data, 0, count);
                                    bytesRead += count;
                                }
                                while (count > 0);
                                inFs.Close();
                            }
                            outStreamEncrypted.FlushFinalBlock();
                            outStreamEncrypted.Close();
                        }
                        outFs.Close();
                    }
                }
            }
        }


        // Decrypt a file using a private key.
        private static void DecryptFile(string inFile, RSA rsaPrivateKey)
        {

            // Create instance of Aes for
            // symmetric decryption of the data.
            using (Aes aes = Aes.Create())
            {
                aes.KeySize = 256;
                aes.Mode = CipherMode.CBC;

                // Create byte arrays to get the length of
                // the encrypted key and IV.
                // These values were stored as 4 bytes each
                // at the beginning of the encrypted package.
                byte[] LenK = new byte[4];
                byte[] LenIV = new byte[4];

                // Construct the file name for the decrypted file.
                string outFile = decrFolder + inFile.Substring(0, inFile.LastIndexOf(".")) + ".txt";

                // Use FileStream objects to read the encrypted
                // file (inFs) and save the decrypted file (outFs).
                using (FileStream inFs = new FileStream(encrFolder + inFile, FileMode.Open))
                {

                    inFs.Seek(0, SeekOrigin.Begin);
                    inFs.Seek(0, SeekOrigin.Begin);
                    inFs.Read(LenK, 0, 3);
                    inFs.Seek(4, SeekOrigin.Begin);
                    inFs.Read(LenIV, 0, 3);

                    // Convert the lengths to integer values.
                    int lenK = BitConverter.ToInt32(LenK, 0);
                    int lenIV = BitConverter.ToInt32(LenIV, 0);

                    // Determine the start position of
                    // the cipher text (startC)
                    // and its length(lenC).
                    int startC = lenK + lenIV + 8;
                    int lenC = (int)inFs.Length - startC;

                    // Create the byte arrays for
                    // the encrypted Aes key,
                    // the IV, and the cipher text.
                    byte[] KeyEncrypted = new byte[lenK];
                    byte[] IV = new byte[lenIV];

                    // Extract the key and IV
                    // starting from index 8
                    // after the length values.
                    inFs.Seek(8, SeekOrigin.Begin);
                    inFs.Read(KeyEncrypted, 0, lenK);
                    inFs.Seek(8 + lenK, SeekOrigin.Begin);
                    inFs.Read(IV, 0, lenIV);
                    Directory.CreateDirectory(decrFolder);
                    // Use RSA
                    // to decrypt the Aes key.
                    byte[] KeyDecrypted = rsaPrivateKey.Decrypt(KeyEncrypted, RSAEncryptionPadding.Pkcs1);

                    // Decrypt the key.
                    using (ICryptoTransform transform = aes.CreateDecryptor(KeyDecrypted, IV))
                    {

                        // Decrypt the cipher text from
                        // from the FileSteam of the encrypted
                        // file (inFs) into the FileStream
                        // for the decrypted file (outFs).
                        using (FileStream outFs = new FileStream(outFile, FileMode.Create))
                        {

                            int count = 0;

                            int blockSizeBytes = aes.BlockSize / 8;
                            byte[] data = new byte[blockSizeBytes];

                            // By decrypting a chunk a time,
                            // you can save memory and
                            // accommodate large files.

                            // Start at the beginning
                            // of the cipher text.
                            inFs.Seek(startC, SeekOrigin.Begin);
                            using (CryptoStream outStreamDecrypted = new CryptoStream(outFs, transform, CryptoStreamMode.Write))
                            {
                                do
                                {
                                    count = inFs.Read(data, 0, blockSizeBytes);
                                    outStreamDecrypted.Write(data, 0, count);
                                }
                                while (count > 0);

                                outStreamDecrypted.FlushFinalBlock();
                                outStreamDecrypted.Close();
                            }
                            outFs.Close();
                        }
                        inFs.Close();
                    }
                }
            }
        }
    }
}

Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates
Imports System.IO
Imports System.Text


' To run this sample use the Certificate Creation Tool (Makecert.exe) to generate a test X.509 certificate and
' place it in the local user store.
' To generate an exchange key and make the key exportable run the following command from a Visual Studio command prompt:
'makecert -r -pe -n "CN=CERT_SIGN_TEST_CERT" -b 01/01/2010 -e 01/01/2012 -sky exchange -ss my

Class Program

    ' Path variables for source, encryption, and
    ' decryption folders. Must end with a backslash.
    Private Shared encrFolder As String = "C:\Encrypt\"
    Private Shared decrFolder As String = "C:\Decrypt\"
    Private Shared originalFile As String = "TestData.txt"
    Private Shared encryptedFile As String = "TestData.enc"


    Shared Sub Main(ByVal args() As String)

        ' Create an input file with test data.
        Dim sw As StreamWriter = File.CreateText(originalFile)
        sw.WriteLine("Test data to be encrypted")
        sw.Close()

        ' Get the certificate to use to encrypt the key.
        Dim cert As X509Certificate2 = GetCertificateFromStore("CN=CERT_SIGN_TEST_CERT")
        If cert Is Nothing Then
            Console.WriteLine("Certificate 'CN=CERT_SIGN_TEST_CERT' not found.")
            Console.ReadLine()
        End If


        ' Encrypt the file using the public key from the certificate.
        EncryptFile(originalFile, CType(cert.PublicKey.Key, RSA))

        ' Decrypt the file using the private key from the certificate.
        DecryptFile(encryptedFile, cert.GetRSAPrivateKey())

        'Display the original data and the decrypted data.
        Console.WriteLine("Original:   {0}", File.ReadAllText(originalFile))
        Console.WriteLine("Round Trip: {0}", File.ReadAllText(decrFolder + originalFile))
        Console.WriteLine("Press the Enter key to exit.")
        Console.ReadLine()

    End Sub

    Private Shared Function GetCertificateFromStore(ByVal certName As String) As X509Certificate2
        ' Get the certificate store for the current user.
        Dim store As New X509Store(StoreLocation.CurrentUser)
        Try
            store.Open(OpenFlags.ReadOnly)

            ' Place all certificates in an X509Certificate2Collection object.
            Dim certCollection As X509Certificate2Collection = store.Certificates
            ' If using a certificate with a trusted root you do not need to FindByTimeValid, instead use:
            ' currentCerts.Find(X509FindType.FindBySubjectDistinguishedName, certName, true);
            Dim currentCerts As X509Certificate2Collection = certCollection.Find(X509FindType.FindByTimeValid, DateTime.Now, False)
            Dim signingCert As X509Certificate2Collection = currentCerts.Find(X509FindType.FindBySubjectDistinguishedName, certName, False)
            If signingCert.Count = 0 Then
                Return Nothing
            End If ' Return the first certificate in the collection, has the right name and is current.
            Return signingCert(0)
        Finally
            store.Close()
        End Try


    End Function 'GetCertificateFromStore

    ' Encrypt a file using a public key.
    Private Shared Sub EncryptFile(ByVal inFile As String, ByVal rsaPublicKey As RSA)
        Dim aes As Aes = Aes.Create()
        Try
            ' Create instance of Aes for
            ' symmetric encryption of the data.
            aes.KeySize = 256
            aes.Mode = CipherMode.CBC
            Dim transform As ICryptoTransform = aes.CreateEncryptor()
            Try
                Dim keyFormatter As New RSAPKCS1KeyExchangeFormatter(rsaPublicKey)
                Dim keyEncrypted As Byte() = keyFormatter.CreateKeyExchange(aes.Key, aes.GetType())

                ' Create byte arrays to contain
                ' the length values of the key and IV.
                Dim LenK(3) As Byte
                Dim LenIV(3) As Byte

                Dim lKey As Integer = keyEncrypted.Length
                LenK = BitConverter.GetBytes(lKey)
                Dim lIV As Integer = aes.IV.Length
                LenIV = BitConverter.GetBytes(lIV)

                ' Write the following to the FileStream
                ' for the encrypted file (outFs):
                ' - length of the key
                ' - length of the IV
                ' - encrypted key
                ' - the IV
                ' - the encrypted cipher content
                Dim startFileName As Integer = inFile.LastIndexOf("\") + 1
                ' Change the file's extension to ".enc"
                Dim outFile As String = encrFolder + inFile.Substring(startFileName, inFile.LastIndexOf(".") - startFileName) + ".enc"
                Directory.CreateDirectory(encrFolder)

                Dim outFs As New FileStream(outFile, FileMode.Create)
                Try

                    outFs.Write(LenK, 0, 4)
                    outFs.Write(LenIV, 0, 4)
                    outFs.Write(keyEncrypted, 0, lKey)
                    outFs.Write(aes.IV, 0, lIV)

                    ' Now write the cipher text using
                    ' a CryptoStream for encrypting.
                    Dim outStreamEncrypted As New CryptoStream(outFs, transform, CryptoStreamMode.Write)
                    Try

                        ' By encrypting a chunk at
                        ' a time, you can save memory
                        ' and accommodate large files.
                        Dim count As Integer = 0

                        ' blockSizeBytes can be any arbitrary size.
                        Dim blockSizeBytes As Integer = aes.BlockSize / 8
                        Dim data(blockSizeBytes) As Byte
                        Dim bytesRead As Integer = 0

                        Dim inFs As New FileStream(inFile, FileMode.Open)
                        Try
                            Do
                                count = inFs.Read(data, 0, blockSizeBytes)
                                outStreamEncrypted.Write(data, 0, count)
                                bytesRead += count
                            Loop While count > 0
                            inFs.Close()
                        Finally
                            inFs.Dispose()
                        End Try
                        outStreamEncrypted.FlushFinalBlock()
                        outStreamEncrypted.Close()
                    Finally
                        outStreamEncrypted.Dispose()
                    End Try
                    outFs.Close()
                Finally
                    outFs.Dispose()
                End Try
            Finally
                transform.Dispose()
            End Try
        Finally
            aes.Dispose()
        End Try

    End Sub


    ' Decrypt a file using a private key.
    Private Shared Sub DecryptFile(ByVal inFile As String, ByVal rsaPrivateKey As RSA)

        ' Create instance of Aes for
        ' symmetric decryption of the data.
        Dim aes As Aes = Aes.Create()
        Try
            aes.KeySize = 256
            aes.Mode = CipherMode.CBC

            ' Create byte arrays to get the length of
            ' the encrypted key and IV.
            ' These values were stored as 4 bytes each
            ' at the beginning of the encrypted package.
            Dim LenK() As Byte = New Byte(4 - 1) {}
            Dim LenIV() As Byte = New Byte(4 - 1) {}

            ' Consruct the file name for the decrypted file.
            Dim outFile As String = decrFolder + inFile.Substring(0, inFile.LastIndexOf(".")) + ".txt"

            ' Use FileStream objects to read the encrypted
            ' file (inFs) and save the decrypted file (outFs).
            Dim inFs As New FileStream(encrFolder + inFile, FileMode.Open)
            Try

                inFs.Seek(0, SeekOrigin.Begin)
                inFs.Seek(0, SeekOrigin.Begin)
                inFs.Read(LenK, 0, 3)
                inFs.Seek(4, SeekOrigin.Begin)
                inFs.Read(LenIV, 0, 3)

                ' Convert the lengths to integer values.
                Dim lengthK As Integer = BitConverter.ToInt32(LenK, 0)
                Dim lengthIV As Integer = BitConverter.ToInt32(LenIV, 0)

                ' Determine the start postition of
                ' the cipher text (startC)
                ' and its length(lenC).
                Dim startC As Integer = lengthK + lengthIV + 8
                Dim lenC As Integer = (CType(inFs.Length, Integer) - startC)

                ' Create the byte arrays for
                ' the encrypted AES key,
                ' the IV, and the cipher text.
                Dim KeyEncrypted() As Byte = New Byte(lengthK - 1) {}
                Dim IV() As Byte = New Byte(lengthIV - 1) {}

                ' Extract the key and IV
                ' starting from index 8
                ' after the length values.
                inFs.Seek(8, SeekOrigin.Begin)
                inFs.Read(KeyEncrypted, 0, lengthK)
                inFs.Seek(8 + lengthK, SeekOrigin.Begin)
                inFs.Read(IV, 0, lengthIV)
                Directory.CreateDirectory(decrFolder)
                ' Use RSA
                ' to decrypt the AES key.
                Dim KeyDecrypted As Byte() = rsaPrivateKey.Decrypt(KeyEncrypted, RSAEncryptionPadding.Pkcs1)

                ' Decrypt the key.
                Dim transform As ICryptoTransform = aes.CreateDecryptor(KeyDecrypted, IV)
                ' Decrypt the cipher text from
                ' from the FileSteam of the encrypted
                ' file (inFs) into the FileStream
                ' for the decrypted file (outFs).
                Dim outFs As New FileStream(outFile, FileMode.Create)
                Try
                    ' Decrypt the cipher text from
                    ' from the FileSteam of the encrypted
                    ' file (inFs) into the FileStream
                    ' for the decrypted file (outFs).

                    Dim count As Integer = 0

                    Dim blockSizeBytes As Integer = aes.BlockSize / 8
                    Dim data(blockSizeBytes) As Byte

                    ' By decrypting a chunk a time,
                    ' you can save memory and
                    ' accommodate large files.
                    ' Start at the beginning
                    ' of the cipher text.
                    inFs.Seek(startC, SeekOrigin.Begin)
                    Dim outStreamDecrypted As New CryptoStream(outFs, transform, CryptoStreamMode.Write)
                    Try
                        Do
                            count = inFs.Read(data, 0, blockSizeBytes)
                            outStreamDecrypted.Write(data, 0, count)
                        Loop While count > 0

                        outStreamDecrypted.FlushFinalBlock()
                        outStreamDecrypted.Close()
                    Finally
                        outStreamDecrypted.Dispose()
                    End Try
                    outFs.Close()
                Finally
                    outFs.Dispose()
                End Try
                inFs.Close()

            Finally
                inFs.Dispose()

            End Try

        Finally
            aes.Dispose()
        End Try


    End Sub
End Class

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

#using <System.dll>

using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Permissions;
using namespace System::IO;
using namespace System::Security::Cryptography::X509Certificates;

//Reads a file.
array<Byte>^ ReadFile( String^ fileName )
{
   FileStream^ f = gcnew FileStream( fileName,FileMode::Open,FileAccess::Read );
   int size = (int)f->Length;
   array<Byte>^data = gcnew array<Byte>(size);
   size = f->Read( data, 0, size );
   f->Close();
   return data;
}

[SecurityPermissionAttribute(SecurityAction::LinkDemand, Unrestricted = true)]
int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();

   //Test for correct number of arguments.
   if ( args->Length < 2 )
   {
      Console::WriteLine( "Usage: CertInfo <filename>" );
      return  -1;
   }

   try
   {
      System::Security::Cryptography::X509Certificates::X509Certificate2 ^ x509 =
            gcnew System::Security::Cryptography::X509Certificates::X509Certificate2;

      //Create X509Certificate2 object from .cer file.
      array<Byte>^rawData = ReadFile( args[ 1 ] );

      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 = gcnew 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." );
   }

}

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
        {
            byte[] rawData = ReadFile(args[0]);
            //Create X509Certificate2 object from .cer file.
            X509Certificate2 x509 = new X509Certificate2(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.");
        }
    }
}

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

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 - 1) 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

Remarks

The X.509 structure originated in the International Organization for Standardization (ISO) working groups. This structure can be used to represent various types of information including identity, entitlement, and holder attributes (permissions, age, sex, location, affiliation, and so forth). Although the ISO specifications are most informative on the structure itself, the X509Certificate2 class is designed to model the usage scenarios defined in specifications issued by the Internet Engineering Task Force (IETF) Public Key Infrastructure, X.509 (PKIX) working group. The most informative of these specifications is RFC 3280, "Certificate and Certificate Revocation List (CRL) Profile."

Important

Starting with the .NET Framework 4.6, this type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the "Using an Object that Implements IDisposable" section in the IDisposable interface topic.

For apps that target the .NET Framework 4.5.2 and earlier versions, the X509Certificate2 class does not implement the IDisposable interface and therefore does not have a Dispose method.

Constructors

X509Certificate2()	Obsolete. Initializes a new instance of the X509Certificate2 class.
X509Certificate2(Byte[], SecureString, X509KeyStorageFlags)	Initializes a new instance of the X509Certificate2 class using a byte array, a password, and a key storage flag.
X509Certificate2(Byte[], SecureString)	Initializes a new instance of the X509Certificate2 class using a byte array and a password.
X509Certificate2(Byte[], String, X509KeyStorageFlags)	Initializes a new instance of the X509Certificate2 class using a byte array, a password, and a key storage flag.
X509Certificate2(Byte[], String)	Initializes a new instance of the X509Certificate2 class using a byte array and a password.
X509Certificate2(Byte[])	Initializes a new instance of the X509Certificate2 class using information from a byte array.
X509Certificate2(IntPtr)	Initializes a new instance of the X509Certificate2 class using an unmanaged handle.
X509Certificate2(ReadOnlySpan<Byte>, ReadOnlySpan<Char>, X509KeyStorageFlags)	Initializes a new instance of the X509Certificate2 class from certificate data, a password, and key storage flags.
X509Certificate2(ReadOnlySpan<Byte>)	Initializes a new instance of the X509Certificate2 class from certificate data.
X509Certificate2(SerializationInfo, StreamingContext)	Obsolete. Initializes a new instance of the X509Certificate2 class using the specified serialization and stream context information.
X509Certificate2(String, ReadOnlySpan<Char>, X509KeyStorageFlags)	Initializes a new instance of the X509Certificate2 class using a certificate file name, a password, and a key storage flag.
X509Certificate2(String, SecureString, X509KeyStorageFlags)	Initializes a new instance of the X509Certificate2 class using a certificate file name, a password, and a key storage flag.
X509Certificate2(String, SecureString)	Initializes a new instance of the X509Certificate2 class using a certificate file name and a password.
X509Certificate2(String, String, X509KeyStorageFlags)	Initializes a new instance of the X509Certificate2 class using a certificate file name, a password used to access the certificate, and a key storage flag.
X509Certificate2(String, String)	Initializes a new instance of the X509Certificate2 class using a certificate file name and a password used to access the certificate.
X509Certificate2(String)	Initializes a new instance of the X509Certificate2 class using a certificate file name.
X509Certificate2(X509Certificate)	Initializes a new instance of the X509Certificate2 class using an X509Certificate object.

Properties

Archived	Gets or sets a value indicating that an X.509 certificate is archived.
Extensions	Gets a collection of X509Extension objects.
FriendlyName	Gets or sets the associated alias for a certificate.
Handle	Gets a handle to a Microsoft Cryptographic API certificate context described by an unmanaged PCCERT_CONTEXT structure. (Inherited from X509Certificate)
HasPrivateKey	Gets a value that indicates whether an X509Certificate2 object contains a private key.
Issuer	Gets the name of the certificate authority that issued the X.509v3 certificate. (Inherited from X509Certificate)
IssuerName	Gets the distinguished name of the certificate issuer.
NotAfter	Gets the date in local time after which a certificate is no longer valid.
NotBefore	Gets the date in local time on which a certificate becomes valid.
PrivateKey	Obsolete. Gets or sets the AsymmetricAlgorithm object that represents the private key associated with a certificate.
PublicKey	Gets a PublicKey object associated with a certificate.
RawData	Gets the raw X.509 public data of a certificate.
RawDataMemory	Gets the raw X.509 public data of a certificate.
SerialNumber	Gets the serial number of a certificate as a big-endian hexadecimal string.
SerialNumberBytes	Gets the big-endian representation of the certificate's serial number. (Inherited from X509Certificate)
SignatureAlgorithm	Gets the algorithm used to create the signature of a certificate.
Subject	Gets the subject distinguished name from the certificate. (Inherited from X509Certificate)
SubjectName	Gets the subject distinguished name from a certificate.
Thumbprint	Gets the thumbprint of a certificate.
Version	Gets the X.509 format version of a certificate.

Methods

CopyWithPrivateKey(ECDiffieHellman)	Combines a private key with the public key of an ECDiffieHellman certificate to generate a new ECDiffieHellman certificate.
CreateFromEncryptedPem(ReadOnlySpan<Char>, ReadOnlySpan<Char>, ReadOnlySpan<Char>)	Creates a new X509 certificate from the contents of an RFC 7468 PEM-encoded certificate and password protected private key.
CreateFromEncryptedPemFile(String, ReadOnlySpan<Char>, String)	Creates a new X509 certificate from the file contents of an RFC 7468 PEM-encoded certificate and password protected private key.
CreateFromPem(ReadOnlySpan<Char>, ReadOnlySpan<Char>)	Creates a new X509 certificate from the contents of an RFC 7468 PEM-encoded certificate and private key.
CreateFromPem(ReadOnlySpan<Char>)	Creates a new X509 certificate from the contents of an RFC 7468 PEM-encoded certificate.
CreateFromPemFile(String, String)	Creates a new X509 certificate from the file contents of an RFC 7468 PEM-encoded certificate and private key.
Dispose()	Releases all resources used by the current X509Certificate object. (Inherited from X509Certificate)
Dispose(Boolean)	Releases all of the unmanaged resources used by this X509Certificate and optionally releases the managed resources. (Inherited from X509Certificate)
Equals(Object)	Compares two X509Certificate objects for equality. (Inherited from X509Certificate)
Equals(X509Certificate)	Compares two X509Certificate objects for equality. (Inherited from X509Certificate)
Export(X509ContentType, SecureString)	Exports the current X509Certificate object to a byte array using the specified format and a password. (Inherited from X509Certificate)
Export(X509ContentType, String)	Exports the current X509Certificate object to a byte array in a format described by one of the X509ContentType values, and using the specified password. (Inherited from X509Certificate)
Export(X509ContentType)	Exports the current X509Certificate object to a byte array in a format described by one of the X509ContentType values. (Inherited from X509Certificate)
ExportCertificatePem()	Exports the public X.509 certificate, encoded as PEM.
GetCertContentType(Byte[])	Indicates the type of certificate contained in a byte array.
GetCertContentType(ReadOnlySpan<Byte>)	Indicates the type of certificate contained in the provided data.
GetCertContentType(String)	Indicates the type of certificate contained in a file.
GetCertHash()	Returns the hash value for the X.509v3 certificate as an array of bytes. (Inherited from X509Certificate)
GetCertHash(HashAlgorithmName)	Returns the hash value for the X.509v3 certificate that is computed by using the specified cryptographic hash algorithm. (Inherited from X509Certificate)
GetCertHashString()	Returns the SHA1 hash value for the X.509v3 certificate as a hexadecimal string. (Inherited from X509Certificate)
GetCertHashString(HashAlgorithmName)	Returns a hexadecimal string containing the hash value for the X.509v3 certificate computed using the specified cryptographic hash algorithm. (Inherited from X509Certificate)
GetECDiffieHellmanPrivateKey()	Gets the ECDiffieHellman private key from this certificate.
GetECDiffieHellmanPublicKey()	Gets the ECDiffieHellman public key from this certificate.
GetEffectiveDateString()	Returns the effective date of this X.509v3 certificate. (Inherited from X509Certificate)
GetExpirationDateString()	Returns the expiration date of this X.509v3 certificate. (Inherited from X509Certificate)
GetFormat()	Returns the name of the format of this X.509v3 certificate. (Inherited from X509Certificate)
GetHashCode()	Returns the hash code for the X.509v3 certificate as an integer. (Inherited from X509Certificate)
GetIssuerName()	Obsolete. Returns the name of the certification authority that issued the X.509v3 certificate. (Inherited from X509Certificate)
GetKeyAlgorithm()	Returns the key algorithm information for this X.509v3 certificate as a string. (Inherited from X509Certificate)
GetKeyAlgorithmParameters()	Returns the key algorithm parameters for the X.509v3 certificate as an array of bytes. (Inherited from X509Certificate)
GetKeyAlgorithmParametersString()	Returns the key algorithm parameters for the X.509v3 certificate as a hexadecimal string. (Inherited from X509Certificate)
GetName()	Obsolete. Returns the name of the principal to which the certificate was issued. (Inherited from X509Certificate)
GetNameInfo(X509NameType, Boolean)	Gets the subject and issuer names from a certificate.
GetPublicKey()	Returns the public key for the X.509v3 certificate as an array of bytes. (Inherited from X509Certificate)
GetPublicKeyString()	Returns the public key for the X.509v3 certificate as a hexadecimal string. (Inherited from X509Certificate)
GetRawCertData()	Returns the raw data for the entire X.509v3 certificate as an array of bytes. (Inherited from X509Certificate)
GetRawCertDataString()	Returns the raw data for the entire X.509v3 certificate as a hexadecimal string. (Inherited from X509Certificate)
GetSerialNumber()	Returns the serial number of the X.509v3 certificate as an array of bytes in little-endian order. (Inherited from X509Certificate)
GetSerialNumberString()	Returns the serial number of the X.509v3 certificate as a little-endian hexadecimal string . (Inherited from X509Certificate)
GetType()	Gets the Type of the current instance. (Inherited from Object)
Import(Byte[], SecureString, X509KeyStorageFlags)	Obsolete. Populates an X509Certificate2 object using data from a byte array, a password, and a key storage flag.
Import(Byte[], String, X509KeyStorageFlags)	Obsolete. Populates an X509Certificate2 object using data from a byte array, a password, and flags for determining how to import the private key.
Import(Byte[])	Obsolete. Populates an X509Certificate2 object with data from a byte array.
Import(String, SecureString, X509KeyStorageFlags)	Obsolete. Populates an X509Certificate2 object with information from a certificate file, a password, and a key storage flag.
Import(String, String, X509KeyStorageFlags)	Obsolete. Populates an X509Certificate2 object with information from a certificate file, a password, and a X509KeyStorageFlags value.
Import(String)	Obsolete. Populates an X509Certificate2 object with information from a certificate file.
MatchesHostname(String, Boolean, Boolean)	Checks to see if the certificate matches the provided host name.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Reset()	Resets the state of an X509Certificate2 object.
ToString()	Displays an X.509 certificate in text format.
ToString(Boolean)	Displays an X.509 certificate in text format.
TryExportCertificatePem(Span<Char>, Int32)	Attempts to export the public X.509 certificate, encoded as PEM.
TryGetCertHash(HashAlgorithmName, Span<Byte>, Int32)	Attempts to produce a "thumbprint" for the certificate by hashing the encoded representation of the certificate with the specified hash algorithm. (Inherited from X509Certificate)
Verify()	Performs a X.509 chain validation using basic validation policy.

Explicit Interface Implementations

IDeserializationCallback.OnDeserialization(Object)	Implements the ISerializable interface and is called back by the deserialization event when deserialization is complete. (Inherited from X509Certificate)
ISerializable.GetObjectData(SerializationInfo, StreamingContext)	Gets serialization information with all the data needed to recreate an instance of the current X509Certificate object. (Inherited from X509Certificate)

Extension Methods

CopyWithPrivateKey(X509Certificate2, DSA)	Combines a private key with the public key of a DSA certificate to generate a new DSA certificate.
GetDSAPrivateKey(X509Certificate2)	Gets the DSA private key from the X509Certificate2.
GetDSAPublicKey(X509Certificate2)	Gets the DSA public key from the X509Certificate2.
CopyWithPrivateKey(X509Certificate2, ECDsa)	Combines a private key with the public key of an ECDsa certificate to generate a new ECDSA certificate.
GetECDsaPrivateKey(X509Certificate2)	Gets the ECDsa private key from the X509Certificate2 certificate.
GetECDsaPublicKey(X509Certificate2)	Gets the ECDsa public key from the X509Certificate2 certificate.
CopyWithPrivateKey(X509Certificate2, RSA)	Combines a private key with the public key of an RSA certificate to generate a new RSA certificate.
GetRSAPrivateKey(X509Certificate2)	Gets the RSA private key from the X509Certificate2.
GetRSAPublicKey(X509Certificate2)	Gets the RSA public key from the X509Certificate2.