PublicKey PublicKey PublicKey PublicKey Class

Definition

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

public ref class PublicKey sealed
public sealed class PublicKey
type PublicKey = class
Public NotInheritable Class PublicKey
Inheritance
PublicKeyPublicKeyPublicKeyPublicKey

Examples

The following example demonstrates how to use the public key from a X509Certificate2 object to encrypt a file. It also shows how to decrypt the encrypted file using the private key for that certificate.

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 certifcate 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, (RSACryptoServiceProvider)cert.PublicKey.Key);

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

            //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, RSACryptoServiceProvider rsaPublicKey)
        {
            using (AesManaged aesManaged = new AesManaged())
            {
                // Create instance of AesManaged for
                // symetric encryption of the data.
                aesManaged.KeySize = 256;
                aesManaged.BlockSize = 128;
                aesManaged.Mode = CipherMode.CBC;
                using (ICryptoTransform transform = aesManaged.CreateEncryptor())
                {
                    RSAPKCS1KeyExchangeFormatter keyFormatter = new RSAPKCS1KeyExchangeFormatter(rsaPublicKey);
                    byte[] keyEncrypted = keyFormatter.CreateKeyExchange(aesManaged.Key, aesManaged.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 = aesManaged.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
                    // - ecrypted 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(aesManaged.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;
                            int offset = 0;

                            // blockSizeBytes can be any arbitrary size.
                            int blockSizeBytes = aesManaged.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);
                                    offset += count;
                                    outStreamEncrypted.Write(data, 0, count);
                                    bytesRead += blockSizeBytes;
                                }
                                while (count > 0);
                                inFs.Close();
                            }
                            outStreamEncrypted.FlushFinalBlock();
                            outStreamEncrypted.Close();
                        }
                        outFs.Close();
                    }
                }
            }
        }


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

            // Create instance of AesManaged for
            // symetric decryption of the data.
            using (AesManaged aesManaged = new AesManaged())
            {
                aesManaged.KeySize = 256;
                aesManaged.BlockSize = 128;
                aesManaged.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];

                // Consruct 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 postition of
                    // the ciphter text (startC)
                    // and its length(lenC).
                    int startC = lenK + lenIV + 8;
                    int lenC = (int)inFs.Length - startC;

                    // Create the byte arrays for
                    // the encrypted AesManaged 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 RSACryptoServiceProvider
                    // to decrypt the AesManaged key.
                    byte[] KeyDecrypted = rsaPrivateKey.Decrypt(KeyEncrypted, false);

                    // Decrypt the key.
                    using (ICryptoTransform transform = aesManaged.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 offset = 0;

                            int blockSizeBytes = aesManaged.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);
                                    offset += count;
                                    outStreamDecrypted.Write(data, 0, count);

                                }
                                while (count > 0);

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

                }

            }
        }

    }
}
Imports System
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 certifcate 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, RSACryptoServiceProvider))

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

        '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 'Main

    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 RSACryptoServiceProvider)
        Dim aesManaged As New AesManaged()
        Try
            ' Create instance of AesManaged for
            ' symetric encryption of the data.
            aesManaged.KeySize = 256
            aesManaged.BlockSize = 128
            aesManaged.Mode = CipherMode.CBC
            Dim transform As ICryptoTransform = aesManaged.CreateEncryptor()
            Try
                Dim keyFormatter As New RSAPKCS1KeyExchangeFormatter(rsaPublicKey)
                Dim keyEncrypted As Byte() = keyFormatter.CreateKeyExchange(aesManaged.Key, aesManaged.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 = aesManaged.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
                ' - ecrypted 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(aesManaged.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
                        Dim offset As Integer = 0

                        ' blockSizeBytes can be any arbitrary size.
                        Dim blockSizeBytes As Integer = aesManaged.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)
                                offset += count
                                outStreamEncrypted.Write(data, 0, count)
                                bytesRead += blockSizeBytes
                            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
            aesManaged.Dispose()
        End Try

    End Sub 'EncryptFile


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

        ' Create instance of AesManaged for
        ' symetric decryption of the data.
        Dim aesManaged As New AesManaged()
        Try
            aesManaged.KeySize = 256
            aesManaged.BlockSize = 128
            aesManaged.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 ciphter 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 Rijndael 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 RSACryptoServiceProvider
                ' to decrypt the Rijndael key.
                Dim KeyDecrypted As Byte() = rsaPrivateKey.Decrypt(KeyEncrypted, False)

                ' Decrypt the key.
                Dim transform As ICryptoTransform = aesManaged.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 offset As Integer = 0

                    Dim blockSizeBytes As Integer = aesManaged.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)
                            offset += count
                            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
            aesManaged.Dispose()
        End Try


    End Sub 'DecryptFile 
End Class 'Program

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
		{
			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.");
			}
	}

}
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

Remarks

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

Constructors

PublicKey(Oid, AsnEncodedData, AsnEncodedData) PublicKey(Oid, AsnEncodedData, AsnEncodedData) PublicKey(Oid, AsnEncodedData, AsnEncodedData) PublicKey(Oid, AsnEncodedData, AsnEncodedData)

Initializes a new instance of the PublicKey class using an object identifier (OID) object of the public key, an ASN.1-encoded representation of the public key parameters, and an ASN.1-encoded representation of the public key value.

Properties

EncodedKeyValue EncodedKeyValue EncodedKeyValue EncodedKeyValue

Gets the ASN.1-encoded representation of the public key value.

EncodedParameters EncodedParameters EncodedParameters EncodedParameters

Gets the ASN.1-encoded representation of the public key parameters.

Key Key Key Key

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

Oid Oid Oid Oid

Gets an object identifier (OID) object of the public key.

Methods

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)

Applies to