PublicKey Class
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Represents a certificate's public key information. This class cannot be inherited.
public ref class PublicKey sealedpublic sealed class PublicKeytype PublicKey = classPublic NotInheritable Class PublicKey- Inheritance
-
PublicKey
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 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 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(AsymmetricAlgorithm) |
Initializes a new instance of the PublicKey class using SubjectPublicKeyInfo from an AsymmetricAlgorithm. |
| 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 |
Gets the ASN.1-encoded representation of the public key value. |
| EncodedParameters |
Gets the ASN.1-encoded representation of the public key parameters. |
| Key |
Obsolete.
Gets an RSA derived object or a DSA derived object representing the public key. |
| Oid |
Gets an object identifier (OID) object of the public key. |
Methods
| CreateFromSubjectPublicKeyInfo(ReadOnlySpan<Byte>, Int32) |
Creates a new instance of PublicKey from a X.509 SubjectPublicKeyInfo. |
| Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
| ExportSubjectPublicKeyInfo() |
Exports the current key in the X.509 SubjectPublicKeyInfo format. |
| GetDSAPublicKey() |
Gets the DSA public key, or |
| GetECDiffieHellmanPublicKey() |
Gets the ECDiffieHellman public key, or |
| GetECDsaPublicKey() |
Gets the ECDsa public key, or |
| GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
| GetRSAPublicKey() |
Gets the RSA public key, or |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
| ToString() |
Returns a string that represents the current object. (Inherited from Object) |
| TryExportSubjectPublicKeyInfo(Span<Byte>, Int32) |
Attempts to export the current key in the X.509 SubjectPublicKeyInfo format into a provided buffer. |
Applies to
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