X509Certificate.GetPublicKey Method

Reference

Definition

Namespace:: System.Security.Cryptography.X509Certificates

Assemblies:: netstandard.dll, System.Security.Cryptography.X509Certificates.dll

Assemblies:: netstandard.dll, System.Security.Cryptography.dll, System.Security.Cryptography.X509Certificates.dll

Assemblies:: netstandard.dll, System.Security.Cryptography.dll

Assembly:: System.Security.Cryptography.X509Certificates.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: X509Certificate.cs

Source:: X509Certificate.cs

Source:: X509Certificate.cs

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.

Returns the public key for the X.509v3 certificate as an array of bytes.

public:
 virtual cli::array <System::Byte> ^ GetPublicKey();

public virtual byte[] GetPublicKey();

abstract member GetPublicKey : unit -> byte[]
override this.GetPublicKey : unit -> byte[]

Public Overridable Function GetPublicKey () As Byte()

Returns

Byte[]

The public key for the X.509 certificate as an array of bytes.

Exceptions

CryptographicException

The certificate context is invalid.

Examples

The following example uses the GetPublicKey method to return a certificate's public key as an array of bytes and displays it to the console.

using namespace System;
using namespace System::Security::Cryptography::X509Certificates;
int main()
{
   
   // The path to the certificate.
   String^ Certificate = "Certificate.cer";
   
   // Load the certificate into an X509Certificate object.
   X509Certificate^ cert = X509Certificate::CreateFromCertFile( Certificate );
   
   // Get the value.
   array<Byte>^results = cert->GetPublicKey();
   
   // Display the value to the console.
   System::Collections::IEnumerator^ enum0 = results->GetEnumerator();
   while ( enum0->MoveNext() )
   {
      Byte b = safe_cast<Byte>(enum0->Current);
      Console::Write( b );
   }
}


using System;
using System.Security.Cryptography.X509Certificates;

public class X509
{

    public static void Main()
    {

        // The path to the certificate.
        string Certificate =  "Certificate.cer";

        // Load the certificate into an X509Certificate object.
        X509Certificate cert = X509Certificate.CreateFromCertFile(Certificate);

        // Get the value.
        byte[] results = cert.GetPublicKey();

        // Display the value to the console.
        foreach(byte b in results)
        {
            Console.Write(b);
        }
    }
}

Imports System.Security.Cryptography.X509Certificates




Public Class X509
   
   
   Public Shared Sub Main()
      
      ' The path to the certificate.
      Dim Certificate As String = "Certificate.cer"
      
      ' Load the certificate into an X509Certificate object.
      Dim cert As X509Certificate = X509Certificate.CreateFromCertFile(Certificate)
      
      ' Get the value.
      Dim results As Byte() = cert.GetPublicKey()
      
      ' Display the value to the console.
      Dim b As Byte
      For Each b In  results
         Console.Write(b)
      Next b
   End Sub
End Class

Remarks

This value corresponds to the contents of the subjectPublicKey field of the SubjectPublicKeyInfo data within the certificate.

Applies to

Product	Versions
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.3, 1.4, 1.6, 2.0, 2.1

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